National Party leader John Key says it is not meddling to force the New Zealand Superannuation Fund to invest 40% of its money in New Zealand.
But opponents of National's policy say it would undermine the independence of the fund and turn it into a political plaything.
As a much more interventionist policy, it would require legislation to direct the fund to change its present investment policy.
However, Mr Key says that is not meddling and the fund would not be told which assets it should invest in.
"I don't support going in and telling the guardians that they should invest in the x, y, z area. I certainly do support more being invested in New Zealand. I think that's the right thing, We are investing in our future, you know, for our future," he said on Thursday 16 October.
Labour Party finance spokesperson Michael Cullen maintains National's policy would undermine the independence of the fund, and make the issue a political football.
"What you end up with is a position where the fund can be used for any political purpose and it completely loses its primary purpose, and that puts New Zealand Super and the future provision of New Zealand Super right back on the political agenda."
Earlier Dr Cullen told Morning Report that National's plan to have 40% of the fund invested in New Zealand shows the party wants to set up part of the scheme as a private piggy bank.
But Mr Key says the fund's guardians would not be told what investments they should make.
He says they would have total discretion over the way it is managed and denied National is using the fund as a political football.
Mr Key says New Zealand needs capital from the fund to be used over a wide range of assets.
He says the party's plan to have at least 40% of the money from the fund invested in New Zealand is a sensible move to put the country on a higher growth path.
The Green Party and New Zealand First support National's policy, along with cautious support from United Future, but ACT Party leader Rodney Hide says it would turn the fund into a political plaything.
'Dopey' - ACT
Mr Hide says National's plan is a dopey, knee-jerk reaction to the global financial crisis.
He says the fund would not provide the best return possible if politicians were dictating how it should be invested.
Mr Hide says it would be too easy for them to insist on investment in their favourite projects, making the fund a political plaything.
He says the fund would be forced to invest more in New Zealand than it otherwise would, which is not a smart move or the best protection for the fund.
Take care - Greens
Green Party co-leader Russel Norman says the Greens have long been calling for such a move.
But he says it is important that it is done very carefully so the Superannuation Fund does not lose any money in the process of selling its shares.
Dr Norman says it would be a perfect opportunity to get the fund out of some of its ethically bad investments, such as nuclear weapons manufacture.
Weak copy - NZ First
New Zealand First leader Winston Peters says National's policy is a watered down version of his own party's idea.
Mr Peters says New Zealand First has always said the fund should be entirely invested in New Zealand.
Cautious support - United Future
United Future Party leader Peter Dunne says he is "cautiously supportive" of the National Party's proposal.