The Labour Party says Trade Minister Tim Groser has left himself open to accusations of a conflict of interest by not declaring his shareholding in a farming company.
Labour MP Darren Hughes says Mr Groser should have declared the 40,000 shares he holds, through a trust, in New Zealand Farming Systems Uruguay.
The company develops dairy farms in Uruguay and is the subject of a takeover bid by Olam International of Singapore.
A spokesperson for the Prime Minister says Mr Groser has declared all his interests, as required by the pecuniary interests register and the Cabinet Manual.
But Mr Hughes says ministers are meant to avoid even the perception of a conflict of interest and just declaring his interest in the trust was not good enough.
He says Mr Groser and Mr Key are relying on technicalities to get them off the hook.
