The federal government spent more than $400,000 sending Environment Minister Greg Hunt and senior public servants on a flurry of overseas lobbying trips to avoid an embarrassing "in danger" listing for the Great Barrier Reef.

Mr Hunt has not yet revealed full details of the bill he personally accrued during the 18-month diplomatic onslaught, which includes $25,000 for travel to the Philippines, Malaysia and Vietnam.

While the cost of Mr Hunt's trips to 11 other countries, along with that of one other government official, is not yet known, it is likely that the total burden on taxpayers will exceed $500,000.

The travel spending came after the Abbott government cut funding for environment programs and slashed hundreds of jobs from the Department of the Environment.