The 11th-hour intervention by the government last week averted a 24-hour shutdown of many of the city’s public bus routes, with 1000 drivers working for operators Transdev and CDC preparing to walk off the job.

But there was a price to pay, with the government agreeing to underwrite a $1800 one-off superannuation top-up for each bus driver and 1 per cent of the 4 per cent pay rise won by the Transport Workers Union for its members.

The deal may have cost taxpayers in excess of $3.5 million but the government continued to refuse on Monday to officially release the cost of the settlement.

Premier Daniel Andrews said the state had got value from the arrangement.

“We think avoiding the industrial action, a fair award for bus drivers in partnership with the private company that runs it, we think is a fair and balanced outcome and is absolute value,” Mr Andrews said.

“Those arrangements are all about value and making sure we can improve and enhance services.”

Mr Andrews referred detailed questions to the offices of Public Transport Minister Jacinta Allan and Treasurer Tim Pallas who brokered the in-principle agreement between the union and the bus operators.

“I’m more than happy to get them to come back to you and take you through those details,” the Premier said.

But Ms Allan’s office was not happy to release the figures with the minister’s spokesperson telling The Age that the government had “nothing to say” until the bus drivers voted on Wednesday on whether to accept the agreement.

Opposition Leader Matthew Guy said the agreement was another example of a cosy deal between Labor, which had an acrimonious dispute with the bus lobby group the Victorian Bus Association recently, and a trade union.

“It’s amazing how the Labor government can do a deal with the Transport Workers Union but they wanted to ride roughshod over the Bus Association,” Mr Guy said.

“They work with one, which is a union and they ride roughshod over another, which is a private business.”