A key challenge facing the Andrews Labor Government when Parliament resumes for the year will be the Upper House, where the Greens and several micro parties now hold the balance of power.

Victorian voters elected five Greens MPs to the Upper House last November as well as two from the Shooters and Fishers, and one each from the Sex Party, the Democratic Labour Party (DLP) and Vote One Local Jobs.

Labor has 14 MPs and the Coalition has 16.

In order to pass a bill or motion, 21 votes are needed in the 40-member Upper House.

Any legislation or motion that is opposed by the Coalition will need the support of all five Greens and two of the other crossbenchers.

The new MPs maintained the Government had a mandate to deliver on its election promises and said they had no plans to hold the Government to "ransom" over special issues.

The Greens had already flexed their muscles, siding with the Coalition late last year to select Liberal MP Bruce Atkinson as the President of the Upper House, ahead of Labor's candidate Gail Tierney.

Mr Atkinson said he did not believe the minor parties in Victoria's Upper House would cause the sorts of problems the Federal Government had faced from the Senate in Canberra.

"I'm not anticipating any misbehaviour. I don't see a similar situation developing to the Senate," Mr Atkinson said.

"I think the members we've got are some very well qualified people across the entire chamber and I think their contributions to debate will be very positive and constructive."

Upper House could 'slow down' Government's agenda

Labor was also confident it would be able to win the support of most of the crossbench for its legislative agenda.

Leader of the Government in the Upper House Gavin Jennings said the Greens were most likely to cause headaches for the Government in the Upper House.

"The real challenge at the moment is the bloc that may be forming between the Liberal Party, the National Party and the Greens, who if they vote on mass on every issue, will defeat the Government and the crossbench," he said.

Mr Jennings said the Greens and the Coalition may not necessarily join forces to defeat legislation but could significantly slow down the Government's agenda.

"They are showing indications of somewhat being very determined to consume the time of the Government through scrutiny measures," he said.

"We're happy to do it, but we don't want to spend all of our time dealing with those matters.

"They're not really dealing with contemporary issues but trying to relive some of the issues of the Bracks and Brumby administration."

Balance of power to deliver openness, integrity: Greens

Before the election Labor worked hard to distance itself from the Greens, which it was battling in a number of key inner-city seats.

Greens leader Greg Barber said he was suspicious of what the Government might do to woo the other crossbenchers.

"Daniel Andrews swore on a stack of bibles: no deals with the Greens," Mr Barber said.

"But he hasn't ruled out dealing with the Shooters or the Sex Party or even [Opposition Leader] Matthew Guy."

He said it would be the job of the Greens to hold both the new Labor Government and the former Coalition government to account in the Upper House.

"The voters didn't want any one party to control the Parliament," he said.

"They wanted openness, transparency and integrity in government and only a balance of power situation can deliver that."

It is not unusual for the government of the day not to have a majority in Victoria's Legislative Council.

President Bruce Atkinson said the diversity of views in the Upper House was a positive.

"I find that where votes are not guaranteed by one party having a majority the debate actually improves," he said.

"I think because there's an opportunity to change people's minds in the course of that debate.

"I'm looking forward to that because the Parliament will work very well and the house will work well as a house of scrutiny."

About 30 per cent of voters backed a minor party in the Upper House at November's election.

Mr Barber said it was a sign of growing dissatisfaction with the major parties.

"The voters chose a different way," he said.

"They've lost a lot of faith in our governing system so instead they've set up a parliament where no one has absolute control."