Health Minister Michael Ferguson should have driven himself to a press conference in Hobart instead of spending almost $800 on a private chauffeured car, according to the public sector union.
Figures released yesterday in State Parliament revealed the Launceston-based MP spent $766 in May on a private car to travel return to Hobart.
Cabinet signed off on a plan in April to get rid of three cars and three drivers from the ministerial car fleet by moving to a pool system in a bid to save about $500,000 a year.
The move was criticised at the time by the Community and Public Sector Union who labelled it ''impractical'' and would result in MPs having to walk or get a taxi if a driver was unavailable.
Opposition Leader Bryan Green unleashed a Right to Information request in question time yesterday that showed chauffeured cars had been used on three other occasions by ministers, with the tax-payer footing a total bill of $988.
Mr Green asked Premier Will Hodgman whether Mr Ferguson would pay the amount back.
''We will not be paying back money we have actually saved the state of Tasmania,'' Mr Hodgman told parliament.
''If we had used the equivalent of the ministerial vehicles, that would have been $1120,'' he said.
Mr Hodgman said the government had saved $27,000 in the three months to July by reducing ministerial car numbers.
All state MPs have access to a car, and do not have to pay for petrol.
Education Minister Jeremy Rockliff has previously said that MPs would make use of their cars if a driver was not available.
CPSU secretary Tom Lynch said hiring a private taxi was ''outrageous'' and it was clear ministers would not drive themselves.
''Why didn't he get in his publicly funded car and drive himself to Hobart?'' Mr Lynch said.
.''I applaud them for making savings, but don't leave a publicly funded car in the driveway and get a taxi,'' Mr Lynch said.