That would require a law change which the Government has been willing to negotiate.
Prime Minister John Key said yesterday at his post-Cabinet press conference that he had no progress to report on the talks.
Asked if that was good or bad news, he said, "It's good news because it means the negotiations are on-going.
"It is bad news in the sense that we haven't yet concluded the deal - but I'd like to."
Mr Key has said he approached a number of potential bidders, including SkyCity, to encourage them to tender.
He had made the approach as Tourism Minister having been advised that New Zealand needed a large-scale convention centre.
Opposition parties have used the deal to accuse National of cronyism, in helping big business at the cost of more problem gambling.
When the criticism intensified, the Government argued that the number of poker machines across Auckland had been dropping and would so further - although that is through Auckland Council policy, not Government policy.
Dissatisfaction was highlighted in another area of the survey, with 49.2 per cent of respondents saying the Government was going in the right direction, while 42.1 per cent thought it was not.
That compared with 54.4 per cent agreeing and 36.7 per cent disagreeing in the last Herald-DigiPoll, conducted in November.
Mr Key's popularity as preferred Prime Minister has been dented - the new poll puts him on 63.9 per cent, down from 66.3 per cent just before the November election.
The big shift has been in support for Labour, rising from 28 per cent last November to 34.8 per cent.