Sky City has revealed a potential $128 million funding gap for its controversial international convention centre in Auckland.
Under its agreement with the Government, Sky City would build and design the centre for up to $402 million.
In return, it would be able to operate another 230 gaming machines and 40 tables.
In a statement released a short time ago, Sky City's chief executive, Nigel Morrison, said the estimated cost of the convention centre could now potentially reach up to $530 million.
Mr Morrison said that was because of significant recent and expected construction cost inflation.
He said Sky City and the Government would need to identify ways to fund costs over and above the $402 million Sky City contract.
Minister of Economic Development Steven Joyce said he learned of the increase recently.
Mr Joyce said he would not rule out taxpayers paying the bill.
He said everything was an estimate until a final construction budget was reached, but he said the top priority was to reduce the ballooned cost.
Mr Joyce ruled out any further expansion of Sky City's gambling facilities to meet the cost.
Nigel Morrison said the preliminary designs of the convention centre, and the total construction cost, would be decided at the end of February.