The Government maintains it has public support for its referendum to change the flag.

Photo: RNZ / Alexander Robertson

On Tuesday, a bill providing for the two-stage referendum passed its second reading 63 votes to 58.

Deputy Prime Minister Bill English sparked off the debate in Parliament with a stinging attack on the opposition.

"I don't look forward to hearing the whinging, backward-looking complaints of the opposition who lack confidence in New Zealand and aspiration for New Zealanders."

But Labour leader Andrew Little was having none of that it.

"I thought that at least the deputy Prime Minister might stand up and tell us what he stood for. He stood there for half his speech with his hands in his pockets and he didn't tell us a thing.

"He stood there, dare I say it, whinging and moaning and carrying on, because the truth is, New Zealanders don't want this change right now," Mr Little said.

He said the country was spending millions on a referendum when it could ill afford it.

All up, the estimated cost of the flag change is nearly $25.7 million, of which $17.3 million will be spent on the two postal referendums, with the rest on public consultation.

Mr English said thousands of people took part in the select committee process and more than 10,000 flag designs were submitted to the flag panel.

That indicated the high level of public interest, he said.

However Green Party MP Russel Norman said the process was skewed.

"The Prime Minister is purposely manipulating the progress to push it towards the outcome he wants."

New Zealand First MP Denis o'Rourke called for the bill to be withdrawn.

He told Parliament the consultation process showed very little public pressure for any flag change.

"The truth is that this Government is pushing this bill against public opinion, not following it," Mr O'Rourke said.

Labour MP Trevor Mallard criticised the nearly $7 million spent on the consultation process as outrageous.

"Do they really think that spending on hall hire, meetings fees and advertising for meetings - $2300 for every person who turned up to those meetings - is good value for money?"

National MP Jono Naylor pointed out that the current flag was New Zealand's third flag - but none of those were decided by the public, which he said was exactly what New Zealanders wanted.

"We're not saying it's a horrible flag, we're not saying that we're not proud of our country.

"But what we are saying is that this is an important issue of national significance and it is one that the people of New Zealand will get to choose," Mr Naylor said.

The legislation will now have its third and final reading in Parliament.

The first part of the referendum is expected to be held later this year, when voters will pick their favourite of four proposed flag designs.