The plan is to extend the station's platforms and take the concourse further out towards West George Street and George Square.
This month Network Rail told Strathclyde Partnership for Transport (SPT) that Transport Scotland had approved the purchase and demolition of its headquarters.
The seven-storey building, Consort House, is on a prime corner site at the station.
If demolition was to go ahead, SPT would need to be compensated to allow it to find and equip another HQ.
The transport agency bought the building in 2005 for about £18 million.
The plan also includes the demolition of part of the Millennium Hotel, which has an extension above the existing station frontage.
This would have to go to make way for the planned redevelopment, which includes a link to Buchanan Galleries.
The demolition would significantly reduce the hotel's capacity and result in a loss of income for Millennium Hotels, one of the UK's and Europe's biggest hospitality chains.
SPT officials will discuss the Queen Street Station plan tomorrow, when concerns over the future of the Queen Street-Anniesland will also be considered.
Fears for the line's viability were revealed in the Evening Times on Tuesday.
In a report to councillors to be considered at the meeting, Eric Stewart, SPT's assistant chief executive, said notification had been given only this month of the intention to demolish Consort House.
He said: "Transport Scotland has given approval for the large scale redevelopment of the station that included the acquisition and demolition of Consort House, mainly due to the estimated future passenger flows at this corner of the station."
Mr Stewart said SPT was awaiting more details of how the purchase would proceed.
Although approval for purchase has been given for Consort House, Network Rail said it had not been confirmed that buying and demolishing it was definite.
It has yet to be determined whether it is wanted or needed, although it has been confirmed negotiations are taking place.
A Transport Scotland spokesman said: "Network Rail is taking forward the commercial negotiations for the purchase of Consort House and Millennium Hotel extension."
A Network Rail spokesman said: "Discussions with SPT and other parties about the redevelopment of Queen Street Station have been continuing since August 2012.
"We are still assessing options for the delivery of the new-look station and plans have yet to be finalised."
No one from Millennium Hotels was available to comment.