Trade Minister Tim Groser owns 40,000 shares in a company which uses New Zealand technology to develop dairy farms in South America but he hasn't broken Parliament's rules.
TV One News reported Mr Groser promoted the NZX-listed company New Zealand Farming Systems Uruguay as part of his job.
The Labour Party says there is a conflict of interest and Mr Groser should sell the shares, but the minister disputes that and says he has met Parliament's reporting requirements.
Prime Minister John Key said he was "absolutely, 100 per cent comfortable ... I've received advice from the Cabinet Office that fully supports Mr Groser's position. He has declared all his interests, as required."
