The Labour Party is promising to invest more in clean technology while also preventing state assets from being sold in the future.
Labour leader David Cunliffe said the $100 million wealth fund - NZ Inc - would be funded by dividends from privatised assets and new royalty payments from the oil and gas industry.
Mr Cunliffe told TVNZ's Q+A programme the wealth fund would use the money to invest in strategic assets and drive growth, with a focus on renewable energy and clean technology.
He said New Zealand can be a world leader in clean technology if the right investments are made.
"This fund has a different mandate: invest in strategic New Zealand assets which are crucial to getting the best possible value out of value chains - how do we get to market - for key New Zealand products."
The fund could also be used to buy back shares in privatised assets where that made commercial sense.
However, Mr Cunliffe said it was important to understand that NZ Inc would not just be an SOE buy-back fund.
"This is a fund that will invest to create the maximum benefit for future New Zealand of strategic assets and clean technologies.
"Some of those might happen to be shares in previous SOEs, but many of them will be in young companies that have particular potential to drive value in the New Zealand economy."
National Party associate finance spokesperson Steven Joyce said experimental clean-tech investments have lost money the world over.
He Labour's spending proposals would push up interest rates and stall the economy.
Pledge to stop future asset sales
The Labour leader also pledged to prevent any future government from selling state-owned assets.
Mr Cunliffe said Labour would create a "KiwiShare" programme for every State Owned Enterprise (SOE) and mixed ownership company, equivalent to the current state ownership level.
He said the programme would enshrine the ownership of public assets by preventing more selldowns.
Mr Cunliffe told TVNZ's Q+A programme that while a future government could change the law to allow sales, it would be very difficult for them to do so.
"They could, if they wanted to, change the law and then scrap the shares in the future. But that would be a very public and a very politically difficult thing to do."
Mr Cunliffe also pledged to conduct a review into the management of the Crown's commercial assets.