And he says the present state of New Zealand's superannuation system does not warrant National coming up with a major alternative to it.

The Government pushed legislation establishing the fund through its final stages in Parliament this week, despite opposition from National, Greens and ACT.

The new law means billions of dollars will be set aside over the next 25 years to help pre-fund the bulge in superannuation payments caused by ageing baby boomers. The Government has committed $600 million as a first instalment.

Finance Minister Michael Cullen has challenged National to come up with an alternative since it opposes the fund but Mr English told NewsRoom that National does not feel compelled to.

He argues that apart from the Cullen fund, New Zealand has reached the greatest consensus in years on publicly provided superannuation, with the bigger parties agreeing the country can afford it.

"What we have got now is actually not too bad and if we get on with the boring but vital task of raising productivity then we are all going to have a bigger pie to share," he said.

"We [National] are not out to try and devise some large-scale alternative savings scheme; that is fundamentally the wrong economic strategy."

National's approach to superannuation hinged on economic growth and prosperity, not government savings.

"We're not guaranteeing a certain standard of living in 40 years time. We believe that we are better to focus on increasing that standard of living than on trying to lock in the current standard of living, which Dr Cullen is doing.

"He's saying 'I'm going to over-tax you now so that in 40 years' time I can deliver you the same standard of living you would get now if you were old'.

"We are saying the best security is a strong economy and then, secondly, political agreement about what should be paid to superannuitants. At the moment we have political agreement about what should get paid to superannuitants but we have a government who thinks they are better to run big savings schemes than have a strong economy."

The first thing a National government would do was stop contributions to the new fund, he said, and that would mean repealing part of the superannuation legislation passed this week "if that's what it takes".

He believes that the contributions will put huge fiscal pressure on the Government. "Whatever happens, a government before very long is going to have to own up to the fact that they are borrowing the money, and the operating surpluses won't be big enough anyway."

A National government would treat the money already set aside as a public asset and part of its balance sheet.

"One of the first thing you would look at is whether you would use it to pay off the debt that was raised to fund it."

National's superannuation policy was still "some way off", but Mr English said the party was debating the merits of tax incentives for retirement savings and compulsory superannuation attached to individual accounts.

He said tax incentives had a limited application because they did not help people without enough money to save, "so we are looking at it under a fairly specific type of approach that's focused on long-term savings".

"If people need to consume all their income then that's what they are going to do, and a lot of New Zealanders live on quite low incomes. What they need is the prospect of rising incomes which can only come with a stronger economy, which is why we put a much stronger focus on the economic opportunity than on government savings."

Mr English is cooler on compulsory superannuation, though he said there had been quite a bit of interest in "salary sacrifice" schemes.

There were flaws in any compulsory scheme "and I think those flaws are large enough that I'm not that keen on compulsory schemes".

He said the complexity of a compulsory scheme meant he would not pretend National could develop such a scheme while in Opposition. And it would probably first have to seek a mandate for any compulsory super through a referendum.