The foreign affairs department has defended spending $7.36 million fitting out leased office space for only 15 staff in Qatar.
Labor senator Alex Gallacher told an estimates hearing on Thursday the cost - at $10,000 a square metre - was double the most expensive fit-out ever approved by parliament's public works committee.
The department said there was a high-cost environment in Doha where the practice of landlords was to lease whole floors.
The May budget approved five new posts, including Doha, as part of an expansion of Australia's diplomatic footprint.
Senator Gallacher pointed out that staff would have 60sq m of office space each.
The department said it had looked at 11 different buildings and undertook a market assessment.
There was a national-interest imperative for Australia, in terms of trade and investment, to have a new post in Doha, it said.
Senator Gallacher disputed that assessment, saying trade with Qatar was in the decline with Australian motor vehicle manufacturing ending in 2017, leaving only live animal exports and boxed meat.
He also pointed out there had been only three ministerial visits to Qatar since 2011.
Department secretary Peter Varghese said he imagined that would change if there was a post there.
DFAT is paying $866,000 a year, or $18,000 a week, in rent for the office space in Doha.
