Over $100 million would be put by the New Zealand Superannuation Fund into a public-private partnership fund investing in infrastructure, like schools, hospitals and housing.

The Public Infrastructure Partnership fund is being set up by privately-owned infrastructure manager Morrison&Co, which could invest up to $500m.

Annual fees would require to be paid for availing the facilities, which will be handed back to public ownership after two to three decades.

According to Morrison&Co director Peter Coman, the fund which was not appropriate for all types of public sector infrastructure investment, was basically an alternative funding source.

"The fund is being structured around a profit back to shareholders and the terms could mean that in the long run the public is paying over the odds for the ownership of a public asset," Council of Trade Unions secretary Peter Conway specified.

He continued that the fund may save some money in the short term, since investment was going into public infrastructure from the private sector.

There had been extensive use of private finance initiatives to refurbish almost the entire school stock in Britain.

Moreover, an array of projects, including schools, hospitals, courts and prisons, has been undertaken in Sydney.

"The individuality of schools to best use their facilities in evenings and at other times might be compromised by the wishes by any private enterprise to use those facilities for other purposes that delivered profit rather than service," concluded New Zealand Educational Institute vice-president Ian Leckie.