The Government pressed ahead with its SkyCity conference centre deal despite a Treasury warning that the facility is unlikely to attract many more international visitors.
Newly released documents show the Treasury told the Government it was unconvinced the benefits of the agreement outweighed the costs.
In a briefing paper from January 2012, the Treasury said it doubted an expanded conference centre would bring significantly more attendees.
In fact, it said, New Zealand already attracts a disproportionate share of the international conference market. It was worried that the private benefit to SkyCity will exceed the public benefit to New Zealanders.
Economic Development Minister Steven Joyce said the Treasury is wrong and other studies show the centre will attract thousands to the country.