Has John Key had his "read my lips" moment? Two years ago he promised ratepayers and taxpayers they would not have to stump up a cent for his baby, an international convention centre to be built by casino operator SkyCity at a cost of $400 million.

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That may have been true then but not so now, it appears. Taxpayers may have to dig deep after SkyCity put out the begging bowl and asked the Government to chip in. The price of not doing so, apparently, would be a cheap "eyesore" on Auckland's waterfront. Clearly, $400m doesn't stretch as far as it used to.

Key's obvious willingness to meet SkyCity some, if not all, of the way on its demand for a top-up struck a jarring note on a day when Parliament opened with the prime minister's opening statement and the usual refrain about restraint and cost-cutting. It has also given new Labour leader Andrew Little a tailor-made platform from which to launch his political year.

The centre has plagued National since the deal was first announced in 2013. The deal was supposed to see SkyCity construct a convention centre with no money from the Government so long as it was allowed hundreds more pokie machines to boost its profits.

But it seems the Government failed to nail that down, or even commit SkyCity to a watertight contract. SkyCity is apparently free to return to the negotiating table and has clearly done so knowing it has the Government over a barrel.

A process already sharply criticised by the auditor-general is now looking even shoddier.

Key and his offsider in the deal, Steven Joyce, might be wise to heed the advice in the song The Gambler about their cards. "You've got to know when to hold 'em, know when to fold 'em, know when to walk away, and know when to run."