The New Zealand Superannuation Fund has sold its $2.2 million investment in five companies involved with maintaining nuclear weapons.
The companies are: Babcock and Wilcox, Fluor Corporation, Huntington Ingalls Industries, Jacobs Engineering Group, URS Corporation and Serco - the private operator of Auckland's Mt Eden Prison.
The Super Fund said on Monday it cut ties with the companies because they are involved in the modification and upgrade of nuclear explosive devices.
It said the divestment would not have any financial impact on the overall fund, worth $22 billion.
Prime Minister John Key said the move is appropriate.
"They have set guidelines from the Government and that indicates what their parameters are for investing and they include moral and ethical rules, and my experience in the past is that they follow that.
"So if they've divested a company it must be because the company started engaging, or they weren't fully aware of the activities they were undertaking."