FEARS terrorists could easily obtain the floor plans of Australian embassies abroad has forced the Department of Foreign Affairs and Trade to review its security procedures at overseas missions.

An Australian National Audit Office report has expressed alarm that the floor plans of most Australian diplomatic missions do not carry an official security classification, potentially allowing terrorists to determine the precise office locations of Australian diplomats and ambassadors.

An ANAO report this week into DFAT's management of its leased foreign missions found that building documentation for Australian diplomatic missions overseas, including building floor plans and layouts, "generally did not carry a security classification, or were marked as 'unclassified' at posts and in Canberra."

The ANAO said DFAT initially defended the unclassified nature of the plans on the grounds they did not identify various areas of the chancery.

DFAT said the floor plans were given to third parties when providing fit-outs and refurbishment but that once the floor plans identified the allocation of offices, they were then classified "security-in-confidence".

But the ANAO said this was insufficient. "The ANAO observed that the unclassified floor plans obtained during fieldwork provided sufficient detail to identify some of these features with a reasonable degree of certainty. Information on chancery floor plans and layouts could

be considered sensitive, thus warranting greater protection."

The ANAO noted that in response to the audit, DFAT had agreed to review its procedures for the classification, storage and access to chancery building plans.

Liberal senator Russell Trood said the report revealed "slipshod security arrangements" by DFAT, which was symptomatic of a department that had too few resources. "It defies credibility that the department would not be more careful about the (floor) plans in relation to our missions," Senator Trood told The Australian. "These would be a great asset in the hands of our enemies. It is reflective of a department which continues to stuff up because of insufficient commitment of resources."

In September last year, DFAT was criticised for posting online the layout of the Australian embassy building in Baghdad as part of a tender process.

This week's ANAO report found that DFAT had been largely effective in its management of about 500 leased properties around the world, but said there was a need for more long-term planning and better governance.

It highlighted several bungles, including a series of bizarre condition reports for the Australian chancery building in Brussels, which -- despite not being refurbished -- was reported by DFAT as being in "fair to good" condition in 2002, rising to "good" in 2004 and then "very good" in 2006-09.

"DFAT was not able to advise why the condition of the chancery was upgraded, especially as the chancery condition would have deteriorated over those eight years," the report said.