Mr Humphries said Mr Corbell asked the previous government last year why ACTTAB was moving to Bruce rather than Gungahlin.

"At this time, I, as chief minister, explained to Mr Corbell and his colleagues that it was almost impossible for ACTTAB to be moved to Gungahlin due to cost, particularly the installation of new communications lines/systems," Mr Humphries said.

He said Mr Corbell had said yesterday that there were concerns that forcing ACTTAB to Gungahlin could leave the Government vulnerable to legal action. He had also said there was concern at the potential time lag and cost of installing new communications systems.

Mr Humphries called on the Government to explain to the people of Gungahlin why it could not deliver its promise to move ACTTAB there.

"It is interesting that this information came to light only hours after a public meeting in Gungahlin [on Wednesday] night. I'm sure the community would have preferred to have been told this information by the Minister first hand," he said.

A spokesman for Mr Corbell said no announcement had been made at the meeting as there had been no decision on the matter. The Government was obliged to give the Hindmarsh Group a lease for a block of land at Bruce, but whether the ACTTAB headquarters went there or to Gungahlin was a different matter.

Since coming to power, Labor had seen a Telstra report, which the previous government had not given it at the time, outlining the costs of moving to Gungahlin.

Treasurer Ted Quinlan would take a submission on the location to Cabinet for a decision.