The Abbott government will ignore Commonwealth value-for-money rules on official real estate as it forces the Australian Taxation Office to spend millions on new offices in regional NSW.

The ATO has confirmed there has been no business case or cost-benefit analysis, as required by the Finance Department's rules, for the plan to build a 6500-square-metre office block in downtown Gosford on the state's central coast.

Coalition making good on election promises: Mathias Cormann. Credit:Luis Ascui

The Taxation Office has 6200 desks sitting empty in its buildings around Australia, is shedding up to 4700 jobs and is trying to get out of leases on office space equivalent to two-and-a-half times the size of the Melbourne Cricket Ground's playing surface.

Finance Minister Mathias Cormann says the government is keeping an election promise by going through with the building but the opposition says spending tens of millions of dollars of taxpayers' money without due process looks like "naked pork-barrelling".