Foreign Minister Murray McCully has expressed "deep concern" at the prison sentences imposed by an Egyptian court on three Al Jazeera journalists.
Two of the journalists, including Australian national Peter Greste, were sentenced to seven years in jail on charges of aiding the Muslim Brotherhood and reporting false news. A third was jailed for 10 years.
The trio all denied the charge of working with the now banned Muslim Brotherhood, but were given jail sentences in a trial dismissed by rights groups as a politically motivated sham.
Prosecutors had accused the three - Australian Greste, Canadian-Egyptian Mohamed Fahmy and Egyptian Baher Mohammed - of promoting or belonging to the banned Brotherhood and of falsifying their coverage of protest to hurt Egypt's security and make it appear the country is sliding into civil war.
Mohammed, was given an extra three years for possessing a single bullet at the hearing attended by Western diplomats, some of whose governments summoned Egypt's ambassadors over the case.
The men have been held at Egypt's notorious Tora Prison for six months, with the case becoming a rallying point for rights groups and news organisations around the world.
Al Jazeera, whose Qatari owners back the Brotherhood and have been at odds with Egypt's leadership since Hosni Mubarak was ousted, said the ruling defied "logic, sense and any semblance of justice".
"There is only one sensible outcome now. For the verdict to be overturned, and justice to be recognised by Egypt," Al Jazeera English managing director Al Anstey said in a statement.
The courtroom quickly descended into chaos as the verdict was read out. Shaken and near tears, Greste's brother Michael said: "This is terribly devastating. I am stunned, dumbstruck. I've no other words."
The three men had looked upbeat as they entered the courtroom in handcuffs, waving at relatives who had earlier told journalists they expected them to be freed for lack of evidence.
McCully said press freedom and transparent judicial processes were fundamental to any democracy.
"I have seen nothing to suggest that these three journalists were doing anything other than their job, and the seven-year prison sentences imposed appear to be aimed at silencing critics rather than serving justice," he said today.
"The Egyptian authorities need to understand that the international community is watching closely and will not accept the current verdicts."
McCully joined other western leaders in calling Egyptian authorities to review the case "as a matter of urgency".
Earlier, Prime Minister John Key said the overnight developments were concerning.
"The way that you define a decent society in part, is through freedom of the press, and also that you have an open, transparent and fair judicial system," he said on Firstline.
"Once you start locking up journalists through what doesn't look like due process, then that's very concerning."
US Secretary of State John Kerry, who a day earlier had discussed the case in a meeting with President Abdel-Fattah el-Sissi, denounced the verdict as "chilling and draconian".
The White House called on the government to pardon the defendants or commute their sentences "so they can be released immediately," spokesman Josh Earnest said. El-Sissi has the power to do so. Legal experts say that would come only after appeals are finished, though the constitution does not specify that requirement.
The appeals process could take months, especially since courts soon start a summer break. The defendants would remain in prison during an appeal unless the win a separate "suspension of verdict" ruling.
Britain, whose ambassador was one of several Western diplomats to attend the hearing, said it was summoning the Egyptian ambassador to protest about Monday's ruling.
"Freedom of the press is a cornerstone of a stable and prosperous society," Foreign Secretary William Hague said.
The Dutch foreign minister also summoned Egypt's ambassador.
Australia summoned a senior Egyptian diplomat on Tuesday to protest against the sentencing of a Greste.
A spokeswoman for Foreign Minister Julie Bishop said Bishop had called in the deputy Egyptian ambassador so that Australia could continue to "express their disappointment". She did not have further details about the meeting. The Egyptian ambassador to Australia is in Cairo.
Greste's parents told a news conference in Brisbane on Tuesday their son was not a criminal.
"This man, our son, Peter, is an award-winning journalist. He is not a criminal," said his father, Juris Greste.
"To us, it is not just affecting the Greste family. We put it to you that it is also a slap in the face and a kick in the groin to Australia, as well as all fair-minded people around the world," he said.
Despite the growing outcry, Australian Prime Minister Tony Abbott struck a cautious tone on Tuesday, somewhat softening his government's furious initial reaction.
"I do understand that once the court system has done its work, there are options for presidential acts - presidential clemency, presidential pardons and so on - and that's why I'm not in the business of being critical of the government as such," Abbott told reporters in Canberra.
"What we don't want to do is engage in unhelpful megaphone diplomacy because that won't do Peter Greste any good, it won't do his two Al Jazeera colleagues any good," he said.
The verdict has caused outrage within Australia, with at least one senior politician going so far as to raise the possibility of levelling sanctions against Egypt government, something Abbott's government has so far ruled out.
Senator Christine Milne, the leader of the small opposition Greens Party, warned against putting faith in an Egyptian judicial system she said has already been "shown to be a joke".
"I think our best hope is for President (Abdel Fattah) al-Sisi to intervene and pardon the journalists concerned and let them leave the country but, in order for pressure to build on Egypt, I think we should consider sanctions," she said.
Despite Kerry's condemnation, US concerns have been balanced by an acknowledgement of the importance of Egypt as a longstanding strategic partner in the Middle East.
As well as discussing the transition to democracy, Kerry said Egypt would be given aid in the form of Apache helicopters to use against militants in the Sinai peninsula that borders Israel, highlighting the multiple interests Washington is juggling.
Amnesty International called it a "dark day for media freedom" and other rights groups also condemned the verdicts.
"These... verdicts are a stark admission that in today's Egypt, simply practising professional journalism is a crime and that the new constitution's guarantees of free expression are not worth the paper they are written on," said Sarah Leah Whitson from Human Rights Watch.
Egyptian officials have said the case is not linked to freedom of expression and that the journalists raised suspicions by operating without proper accreditation.
Many Egyptians see Al Jazeera as a force determined to destabilise the country, a view that has been encouraged in the local media, which has labelled the journalists "The Marriott Cell" because they worked from a hotel of the US-based chain.
A video that appeared on a pro-government channel and spread online, reinforced the view that the journalists had sinister intents, showing their arrest in their hotel room, with close-ups of their computers, cameras and communications equipment allegedly used to broadcast lies aimed at undermining security.
Al Jazeera's Cairo offices have been closed since July 3 when security forces raided them hours after Mursi was ousted and criticism of the government and army has virtually vanished from the gamut of Egyptian media since then.
In total, 20 people were sentenced on Monday. They included at least 14 Egyptian defendants who faced charges of belonging to the Muslim Brotherhood.
Of those, two were acquitted including Anas al-Beltagi, the son of a senior Brotherhood official who is in jail. Four recieved seven-year sentences and the rest 10 years in absentia.