But Premier Daniel Andrews has taken aim at the union, saying they should not criticise consultant spending while complaining about increasing work loads.
The CPSU data, released on Thursday, showed the government spent $176.89 million on consultancies in 2021-22, up from $59m in 2014-15.
Federal secretary Karen Batt said consulting agencies were acting as a secret government workforce but coming at a premium price.
"The government continues to make hollow commitments to prune their consultant spend but never deliver while their workforce cops a wage cap and excessive work demands because there's simply not enough staff," she said in a statement on Thursday.
But Mr Andrews criticised the CPSU, saying the union couldn't have it both ways.
"If you're the CPSU complaining about too many consultancies and then complaining if you have to do more work," the premier told reporters on Thursday.
"Let's be clear, we have added the number of people that we need with the expertise that is critically important.
"I'm not here to have a quarrel with that union or anyone really but you've got to be consistent."
KPMG was the top company to receive government work over the past financial year, with the union data showing the agency received close to $32m.
Pricewaterhouse Coopers, Ernst and Young, Deloitte and Allens rounded out the top five, all receiving millions of dollars.
The Department of Transport spent $37.74m on consultants in 2021-22, while the Department of Jobs, Precincts and Regions spent $36.26m.
Before last year's election, Labor promised to save $50 million a year by cutting consulting and labour hire costs.
Mr Andrews did not provide an exact dollar figure on cuts to consultancy costs ahead of the May state budget.
"The budget is not the budget that was delivered five years ago," Mr Andrews said.
"But we will deliver all of our election commitments.
"We had a COVID emergency and we had to go and borrow money to get through, and that money now has to be paid back."
The premier denied the spiralling consultancy costs showed there was brain drain within the public service and said many of the contracts were short term.
"Sometimes you need specialist skills and you wouldn't go and build your own team and have it there," he said.
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