Package includes cutting poker machine numbers from 12,100 to 8,100 by 2023

Support for SA Best’s gambling reform package will be “both a deal-maker and a deal-breaker” should the party win the balance of power at South Australia’s March election, the party’s leader, Nick Xenophon, says.

Unveiled by Xenophon on Monday, the package details measures including reducing the number of poker machines in hotels and clubs from about 12,100 to 8,100 by 2023 and introducing a system of $1 maximum bets per spin.

Xenophon first entered the SA parliament 20 years ago on a platform to rid the state of all poker machines and has come under fire from political opponents over his changed policy.

However, he defended his rethought package as “sensible and practical” and expects support for the policy if SA Best forms a minority government with either major party.

“What we’ve said is that there’s flexibility within the way that you achieve it, but what we’re seeking to achieve is, I think, reasonable,” he told reporters.

“I suggest to you that if SA Best is in a position of power to hold the next government to account, then both Labor and the Liberals will become born again gambling reformers in a very short amount of time.”

The state opposition leader, Steven Marshall, who has ruled out doing a deal with SA Best to form government, said the Liberal party proposed no change to the number of poker machines in the state.

He said Xenophon had compromised his principles and let voters down.

“This is the most astonishing backflip, I think, in electoral history in South Australia,” he said. “He was a ‘no-pokies MP’ now he is an ‘8,000-pokies MP’ … a guy that has sold out on his single-principle policy position.”

The premier, Jay Weatherill, would not comment directly on Xenophon’s policy but said his government was working to minimise the harm of problem gambling.

SA Best’s policy also proposes the removal of Eftpos access near poker machines and a ban on political donations from the gambling industry.

A “buyback” scheme would be introduced to support more than 140 venues with 10 or fewer machines, but Xenophon admitted no modelling had been done to find out how much the package would cost taxpayers.

“To speculate on a figure would not be the right thing to do,” he said. “It would be a huge exercise of modelling; it is not a reasonable task to undertake at this point.”

The South Australian branch of the Australian Hotels Association labelled the policy a “deliberate and planned” destruction of the hotel and club industry.

“This plan will decimate hotels across South Australia, wiping out many of the 26,000 jobs it directly creates,” CEO Ian Horne said. “It would result in many pubs being completely shut.”

Earlier on Radio National, Xenophon claimed it was an “arithmetical impossibility” for him to become premier and the party was “fighting very hard just to win the balance of power”.

With SA Best fielding 35 lower house candidates in the 47-seat parliament and the party polling up to a third of the vote it is possible it could emerge with the largest bloc of seats – or even an absolute majority – making Xenophon premier.

He suggested the major parties could direct their preferences to shut out SA-Best, while his party would run open tickets.

Xenophon denied that SA Best had reached a deal with Labor to support it in government, noting he had sent Marshall a letter warning him he may sue for defamation if he repeated the claim.

Xenophon said negotiations would depend on how many seats each party won and who was prepared to negotiate with SA Best to achieve its platform.

He said his candidates were “not interested” in cabinet positions because “we want to be watchdogs of the executive government and I don’t think you can do that fearlessly if you’re in a cabinet position”.