Federal Treasurer Wayne Swan says the head of his department is perfectly entitled to take leave.
Ken Henry is taking five weeks' leave to work with endangered wombats, it was reported today.
He will miss a Reserve Bank board meeting and be without a mobile phone as he ventures into central Queensland, News Limited said.
Opposition Leader Brendan Nelson has said five weeks was long time for the head of Treasury to take leave, especially at a time when the government was facing issues such as cost-of-living pressures, major tax reform and climate change.
"Dr Henry is perfectly entitled to take leave," Mr Swan told reporters.
"He has done so with my approval.
"It's regrettable that we have had this smear launched against Dr Henry by the Liberal party."
Mr Swan said it was a logical time for Dr Henry to take leave, with the parliamentary session over and with the Treasury Secretary having worked through Christmas and around the clock during the preparation of the May budget.
"There's a lot, lot more to do for the rest of the year and into next year," Mr Swan said.
"Dr Henry will be running the Henry review when it comes to taxation, a lot of work over the next 18 months."
Dr Henry would also be working on the Council of Australian Governments' reforms of federal-state relations and emissions trading.
It was regrettable that Dr Nelson had embarked on a smear campaign regarding Dr Henry's leave, Mr Swan said.
"Dr Nelson thinks it's okay for Alexander Downer to go and play golf, to go to lunch during question time, for Mark Vaile to travel the Middle East as a consultant, but it's not okay for our top public servant to take a few weeks off in the middle of the year when he has worked through Christmas and right through the budget.
"There has been a fair bit of commentary about the working hours of this government.
"The government has been working very hard, senior public servants have been working very hard, and that has been particularly the case in the Treasury, because in the Treasury when you are bringing down the budget you do work around the clock."
