The Council of Trade Unions says it is worried the future of retirement income would be put at risk by National Party's policies.
CTU economist Peter Conway says many would welcome the National Party's plan to force the New Zealand Superannuation Fund to invest 40% of its money in this country but there are concerns about the policy.
"There's some major worries as well, because now with the attack on KiwiSaver and raiding the Super Fund in this way, it does mean the whole issue of income security in retirement has been made a lot less guaranteed for people."
He says the policy would open the way for further meddling in the fund.
Mr Conway says it would essentially be turned from a superannuation fund into a national development fund.
