State parliament has screeched to a halt after the government stormed out before the upper house could vote on a controversial bill to privatise NSW Lotteries.

Leader of the upper house Tony Kelly walked out of the legislative council just before 1am (AEST) on Thursday, forcing an indefinite suspension of house business until he returns, opposition politicians said.

Opposition house leader Mike Gallacher said Mr Kelly called for an adjournment vote one day before the autumn sitting was scheduled to finish, then walked out, forcing upper house president Peter Primrose to suspend business.

Without the leader of opposition present, we cannot continue until he returns, Mr Gallacher said. “It’s now in a limbo situation – we’re not sitting but we’re not adjourned,” he told AAP. “It is incredibly bizarre set of circumstances.”

Mr Gallacher said the upper house had been scheduled to debate and vote on the NSW Lotteries privatisation bill before council adjourned for the winter break on Thursday.

The bill would allow a private operator to run the state’s lotteries under an exclusive long-term licence.

Analysts estimate the licence would last 30 years and pump about $600 million into the treasury.

The opposition does not support the bill, saying it should wait 12 months until economic conditions improve or risk losing up to $100 million over the sale. “It would appear that the government does not enjoy the numbers (a majority in the upper house),” Mr Gallacher said. “Rather than bring the matter on for debate as it was listed to do tonight (Wednesday) the government sought to adjourn the parliament until September.”

Shooters’ Party upper house member Robert Brown said he and colleague Roy Smith would not have supported early adjournment.

With the opposition and Greens opposing the sell-off, the privatisation hinges on the support of the two Shooters’ Party MPs.

According to the coalition, Shooters’ Party support was tied to their controversial bill to allow private game reserves and hunting of native animals in national parks.

But on Tuesday Premier Nathan Rees said Labor would not back the Shooters’ Party proposal – raising doubts about the Lotteries sell-off.

Mr Brown said the government only approached his party on Wednesday and it had not yet given support to the Lotteries bill. “We hadn’t decided anything – we were still negotiating with the government on that bill,” Mr Brown told AAP.

He said the government would have to face questions over the legislation if parliament resumed for its last day on Thursday.

“I guess the government thought that they did not have the numbers in the house so they didn’t really want to spend another day there getting hammered by the Greens and the opposition,” he said.

Comment is being sought from Mr Kelly and other government MPs.