Police are refusing to comment on reports Sydney's busy Central Railway Station was a possible target for explosive chemicals found stockpiled at a Brisbane house.
Nine News says police are investigating if the railway station, and another location in Newcastle, north of Sydney, might have been targets for more than 50 kilograms of explosive material found at a Pullenvale house last week.
Nine says police identified the sites after two crudely-drawn mud maps were found at the house, were officers carried out 17 controlled blasts last week to rid the property of highly volatile chemicals.
They reportedly include three types of peroxide-derived mixers, including one known as DMDT which Nine said was used in the 2005 bombings that targeted London's transport network.
One of the mud maps carried the words "George Street" and "uniform" and an arrow pointing to an intersection.
Police believe it identifies the corner of George Street and Rawson Place, next to Sydney's Central station, Nine said. At the end of the street is a uniform shop.
The other mud map carries the words "brothel", "bridge" and "grave", believed to identify a site in Newcastle where there's a brothel across the road from a cemetery and close to a small railway overpass, Nine said.
Queensland police are refusing to comment on every aspect of the report, saying only that the investigation involves multiple agencies and is ongoing.
They've also declined to answer specific questions, including if they have interviewed the former tenant of the Pullenvale house who is now in custody in Newcastle on unrelated charges.
Australian Federal Police said they are assisting Queensland police, but state officers are in charge of the probe.
Specialist x-ray equipment is reportedly being brought in to look through the walls and the floors of the Pullenvale house.
NSW Police are also refusing to comment on the investigation, despite the suggestion of two potential target sites in the state.
A spokesman for NSW Police Minister Stuart Ayres said he was aware of the incident, but would not be commenting while the police investigation is underway.
Nine has said 29kg of explosive chemicals were found at the house, alongside another 22 litres of liquid explosive material.
They comprised three distinct types of peroxide-derived mixers: TATP, HMDT, and DMDT, with the latter used in the London attacks.
Police have not said if they know the whereabouts of a woman who was living at the Pullenvale house with the man now in custody in Newcastle.
The man is facing charges dating from 2012 of wounding, assault, weapon and drug possession. He's due to face a NSW court again later this month.