Eden-Monaro MP Mike Kelly says he had no say over the fit-out of his electorate office that cost half a million dollars.
He said the costs were partly due to extra security and communications issues related to his position as Minister for Defence Materiel.
The costs were triggered by the relocation of his Queanbeyan electorate office because the owners of the original site were redeveloping.
''Any questions about the re-establishment of our office should be directed to the Department of Finance, I have no say in those matters,'' he said.
''They adopt a template approach to this and, as could be seen from the story, the costs were very similar to fitting out a new office for the Liberal MP Patrick Secker.
''I would note that in Patrick Secker's case, it was a voluntary move, which is, I think, the bigger question to ask as to whether those costs were therefore necessary.
''In my case it was a forced move.''
It was not clear on Wednesday if the taxpayer-funded fit-out would be transferred to his successor if he loses the bellwether seat of Eden-Monaro.
If Liberal candidate Peter Hendy wins, he would be expected to occupy the office, according to the Finance Department.
But Mr Hendy said he would be a backbencher if elected.
''If I were to be lucky enough to win the seat, I would [act] at the direction of the Department of Finance as to where I could put the office and how much could be spent,'' he said.
''I think there's a chance it would be a different location because I understand he [Dr Kelly] has a ministerial office.''
Mr Hendy was chief of staff to Defence Minister Peter Reith in the Howard government.
''I do understand, based on my experience in both the business sector and in government positions, that there are requirements for security for offices and other aspects to ensure ministers have appropriate accommodation,'' he said.
Fairfax Media reported on Wednesday that Dr Kelly received a parliamentary entitlement in the second half of last year of about $810,000, of which $526,737 was spent fitting out his office.
An analysis of the latest expense payment disclosures shows Foreign Minister Bob Carr was at the top of the list, receiving entitlements of $961,234 in the final six months of last year, mainly due to overseas travel totalling $721,577.
South Australian Liberal Mr Secker came in third place with spending of $757,684 - again, largely attributable to an office fit-out costing $505,338.
Dr Kelly said his previous office was part of a redevelopment. ''All of the tenants were evicted and I then spent six months with my team effectively almost camping out in an abandoned office until a new office could be fitted out,'' he said.
''I am the Minister for Defence Material, therefore there are also extra security and communications issues associated with my office.
''I do know they ran into some difficulty with the fit-out because they found the floor was not strong enough for our equipment. So they had to work with the owner to reconcrete the whole floor.
''I would have thought the issue here is not that there was a move of office or costs associated with that but whether those costs were reasonable.''
The Finance Department was asked if office leases have a clause allowing early termination if an MP is defeated, or a provision to recover any costs of renovations.
''Finance routinely requests that an early termination clause be included in a lease during negotiations, however this is subject to the landlord's acceptance,'' a spokeswoman said. ''It is expected that an incoming senator or member will occupy the office vacated by his or her predecessor.
''Commercial property contracts do not generally allow for payments to vacating tenants for these reasons.''