Over the past six months, the government has been in and out of the courts, fighting cases with highly paid lawyers and silks in a series of legal battles that the opposition believes could be costing taxpayers millions of dollars.

But when asked how much the government has spent, a spokesman for Mr Andrews declined to say, telling Fairfax Media: "All legal costs incurred are consistent with the practices of previous governments and will be accounted for in the usual manner in the annual reports."

Twice last year, the government went to the Supreme Court in a bid to block the Ombudsman from probing whether Labor misused funds as part of its 2014 election campaign – and twice it lost. It has now sought leave for a third legal challenge in the High Court.

The government also faced a separate legal stoush over its plan for elevated rail along the Cranbourne-Pakenham train line, which a residents' group, Lower Our Track, had unsuccessfully sought to declare unlawful due to lack of community consultation.

And late last year, the government was in court once again – this time to defend its bid to put youth offenders in the maximum security Barwon Prison. When the Supreme Court and Court of Appeal ultimately ruled that moving children to the adult jail was illegal, the government sought to circumvent the decisions by re-gazetting the Grevillia unit as a youth justice facility.

Liberal shadow attorney-general John Pesutto said Mr Andrews came to office promising open and accountable government, "So why is he refusing to reveal the massive legal costs arising out of litigation like the rorts, Skyrail and youth justice scandals?

"With taxpayer-funded legal fees in the rorts fiasco reaching millions of dollars all to protect the Labor Party and Labor MPs, imagine the difference that would make to a local school or regional hospital," he said.

The government's refusal to disclose the cost of its legal fees is likely to prove sensitive at time when the Premier is already under fire over law and order, government integrity and an apparent lack of transparency.

Such matters came to fore last week, with the government seeking to use State Parliament to stop "current or former members of the Legislative Assembly" – which includes Mr Andrews – from being subject to an inquiry about alleged rorting. The Human Rights Law Centre also announced last week that it would launch a fresh court challenge against the detaining of youths in Barwon Prison, which is likely to bump up the government's legal bill even further.