One of Australia's biggest private bus companies has turned down government funding that would have gone directly to driver wage increases, leaked documents show. 

Bus Queensland has refused a state-subsidised wage deal that would have increased its drivers' wages to $35 per hour in line with other bus companies.

A leaked internal memo shows upper management did not want to accept the government's money because of the costs to implement the wage increases.

The cited implementation costs include increases to accrued annual leave balances as well as wage increases for driving work not covered by the subsidy.

Bus Queensland's school bus routes would not be covered by the government subsidy, but annual leave pay would be. 

The letter, signed off by chief operating officer Paul Davies, claims the company would lose $3 million over three years if it were to pass on the wage increases.

In the letter, Mr Davies objects to the condition that the company send its new drivers to a drivers' forum, which covers topics such as violence, driver safety, and union membership. 

The memo objects to the Transport Workers' Union's heavy involvement with the forum, as well as the costs involved.

"We understand the drivers' forum has been created [possibly amongst other reasons] to provide the TWU with another opportunity to advertise their services," the letter said.

"Whilst the government would subsidise parts of the costs of the new drivers attending the forum, not all costs would be covered and, more critically, this would take new drivers off the road and increase the pressure on our existing drivers and our ability to deliver our contractual requirements.

"None of these extra costs would be met by the government, although we have repeatedly requested they reconsider their position."