THE head of Australia's foreign service admits his department made a mistake by posting confidential details of Australia's embassy building in Iraq online.

The Department of Foreign Affairs and Trade last month put online details of the layout of the new Australian embassy in Baghdad.

During a Senate estimates committee hearing today, DFAT chief Dennis Richardson insisted that no Australian lives had been put at risk by the accidental release of confidential details.

“The only reason to be troubled is that a mistake has been made,” he said.

Mr Richardson said the mistake had been “made on an individual basis” and that the accidental posting of the embassy details was “not systemic”.

When asked by Queensland Liberal senator Russell Trood if the security of the embassy had been put at risk, Mr Richardson gave a categorical “no”, adding: “We've acknowledged the mistake and there is no breach of security.”

The embassy comprises two storeys plus a basement, two apartments, two guardhouses, demountable accommodation, another four-level hall plus basement and a dozen single-level buildings including a gym, laundry and storerooms.

“The detail contained in this request for proposal is confidential,” the document says.

It goes on to outline the finish of rooms, what walls are made of and the type of air conditioning used.

Senator Trood said last month he was worried militants in Iraq could use details from the document to formulate an attack.

“We all know terrorists have made excellent use of the web,” he said.

“I believe in transparency but there are some areas where the security of Australian lives is very important.”