The MPs, mostly from NSW and Queensland, hardened their resolve yesterday as Clubs NSW stepped up its marginal seats campaign by promising to spend at least another $11 million between now and the federal election against reforms to curb problem gambling.

The clubs and hotels industries have already spent $1.8 million on a campaign which has been so effective that MPs report the hostility from their electorates is far greater than that caused by the carbon tax.

Clubs NSW is targeting 31 Labor seats on the east coast, some of which are held by ministers who are bound to support party policy.

But about 25 backbenchers say they will vote in caucus against Mr Wilkie's demand that clubs implement mandatory pre-commitment technology. This technology would require gamblers to nominate in advance how much they were prepared to lose over a certain period. This, plus limits on ATM withdrawals, aims to stem problem gambling.

The parliamentary secretary, Mike Kelly, who holds the marginal NSW seat of Eden-Monaro, has implored Mr Wilkie to consider voluntary pre-commitment with additional funds for counselling and rehabilitation to treat gambling addiction.

''I would not support anything that would threaten the viability of my pubs and clubs,'' Mr Kelly told the Herald. ''They are such an integral part of the community.''

Mr Wilkie, who is backed by the No Pokies Senator Nick Xenophon, insists on mandatory pre-commitment. He will withdraw his support for the minority government if it fails to pass legislation by May 31 next year that would force states to implement the reforms by 2014.

Experts such as the Productivity Commission's Chairman, Gary Banks, said in March that mandatory pre-commitment will be effective in curbing problem gambling but ''would have a significant impact on industry revenue given the high share coming from problem and at-risk gamblers.

''The club industry has tried to position itself as a special case, given its community-based activities but the evidence suggests that only a small proportion of most clubs' gambling revenue tends to be devoted genuinely to public benefit causes.''

The Labor MPs accept that if the caucus voted down the Wilkie deal altogether, it could collapse the government.

One NSW MP, who did not want to be identified, told the Herald that a majority would still support mandatory pre-commitment.

Those who voted against it would at least be able to tell their electorates they opposed Mr Wilkie's demands.

''He's got a closed mind,'' the MP said of Mr Wilkie.

Clubs NSW yesterday launched stage two of its campaign costing $2.5 million. Furthermore, it will keep the annual proceeds of Club Keno to further fund a $9 million war chest for a stage 3 campaign early next year. The Clubs lobby is banking on other interested parties such as the Hotels Association contributing as well.