National Party president Peter Goodfellow says the party and board are "extremely disappointed in Mr Gilmore’s behaviour".
The comment came after Prime Minister John Key said he couldn't "reconcile" Aaron Gilmore's text messages with his version of events of a boozy dinner and has signalled he should stand down.
Key said he couldn't "make him [Gilmore] gone" but he had contacted party president Peter Goodfellow this morning.
"I find them difficult to reconcile with the version of events that Mr Gilmore gave my office," said Key.
"I said at the time if I found it difficult to reconcile those events I'll treat this as a serious matter."
In a statement this afternoon Goodfellow said he would talk with Gilmore "who will need to reflect thoroughly on his future as an MP".
"He has a long way to come back from this,” Goodfellow said.
“No Party can force out a Member of Parliament, however, whatever decision Mr Gilmore makes, there are always consequences in politics.
‘‘At some time next year, National’s List Ranking Committee will meet to determine the list for the next election.”
Key hasn't asked Gilmore to resign, but has said: "Given the pressure he's been under and the questions he's been unable to answer to the media, I would have thought it was self explanatory for him to come forward if that's what he wants to do."
Key also said: "No party can force a member out of Parliament out... even if we were to try and sack him out of caucus... that is a long, drawn out and quite painful and expensive process.
"What I am saying is that we are 59th out of 59, he has no portfolio responsibilties, he is a list member of Parliament and I have expressed my real concerns to the party president.''
Asked what the party should do, he said: "I can't prejudge that process. I mean obviously the list ranking committee will need to go through its work when it re-evaluates the list next year.
"But it will need to take into consideration a wide range of factors and I would expect them to take into consideration this factor."
Rather than taken formal proceedings to expel Gilmore, Key said it may be quicker to wait until next year's election.
"I don't think we will move to expel him from the caucus because, quite frankly, I'm not sure if that would be a faster process."
Asked to express confidence in Gilmore, he said: "He has some merits but I find it difficult to reconcile those particular statements. I am confident he can carry out his work as a member of Parliament. I am also confident that he needs to change his behaviour and his drinking habits as displayed on that particular night."
Key said he had a country to run and people expected him to focus on that.
Gilmore wasn't in the House for Question Time and he also did not make a meeting this morning. At his office fellow MP Sam Lotu-Iiga said he was not available.
This morning the National Party was shown text messages from Gilmore that appear to contradict assurances he gave Key.
The revelations came amid news the under-fire list MP did not show up to a regular meeting at Parliament this morning.
Gilmore fronted up to Parliament yesterday to make a public apology for his behaviour at a dinner at a Hanmer Springs hotel on April 27, but denied that he threatened to have Key intervene to have a barman sacked.
However, an exchange of text messages between Gilmore and Christchurch lawyer Andrew Riches was circulated among senior National Party figures yesterday, including general manager Greg Hamilton.
Riches was so embarrassed by the MP's behaviour at a dinner on April 27 that he left the waiter an apology note.
In a text on May 2, Riches said: "I didn't write that note because we were boisterous, I wrote it because you told the guy he was being fired, said the PM would be involved and I didn't want the poor guy to worry about his job."
Gilmore does not dispute Riches' recollection of events, replying: "I know. They are trying to make it seem bigger than that. It's bullshit. I've taken the blame and apologised. Just say nothing."
Riches was annoyed Gilmore issued a statement apologising for the behaviour of the group, which included Riches and their partners.
"You didn't take the blame. You blamed the rest of your group," Riches wrote back.
Gilmore also appears to further insult the barman in the texts. He replied: "I did the f....... said I was not the only one drink [sic]."
At a press conference yesterday Gilmore made a series of apologies to the barman, his partner, family, the National Party, and fellow MPs.
He admitted he called the waiter a "dick" or "dickhead", that he was rude and had behaved like a bully.
"I'm sorry for my arrogance and rudeness to the barman when I was leaving the restaurant. If there was a dickhead that night it was me.
"No service industry worker deserved to be treated rudely. I behaved badly and I crossed the line. It will not happen again."
However, he denied that he invoked Key's name or that he had asked the barman, "Do you know who I am?"
"There was no involvement of the prime minister's office," he insisted.
"I had a discussion with the barman over my understanding of the liquor laws, and that I understood someone could be fired if they served a drunk person ... I did not use the words 'Do you know who I am?'"
He went on: "He [the barman] didn't know who I was ... I said, 'I'm a member of Parliament ... He then said, 'Do you know the prime minister?' My response was, 'Yes, I work for him'."
He said Riches had "as much, if not more, to drink than I" but denied he was accusing Riches of lying.
Riches, who won a bravery award for rescuing survivors from the collapsed PGC building after the 2011 earthquake, stood by his original statement yesterday.
"I will be making no further comment and will allow the public to draw their own conclusions."
- © Fairfax NZ News
Should the NZ delegation to Nelson Mandela's funeral include 1981 tour protesters?Related story: Kiwi Mandela delegation without tour protesters