Prime Minister John Key says the Government has nominated Trade Minister Tim Groser for the top post at the World Trade Organisation.

Mr Groser, a former trade diplomat, was nominated to replace current director-general Pascal Lamy today, although the consensus voting by WTO members will not occur until May 2013.

"Given Tim Groser's experience in trade, and the blend of both technical and political skills he brings to the table, I believe he is well placed to advance the complex and challenging issues facing the WTO," Mr Key said.

Mr Groser said he felt honoured by the nomination from the New Zealand Government for the role.

"I have spent most of my professional life working to advance international trade issues and consider the WTO to be of fundamental importance to global economic development and prosperity.

"The past few years have placed great stress on the multilateral trading system and the next few years will be critical in maintaining the WTO's relevance and value for its members," said Mr Groser.

Mr Groser has been the Minister of Trade since 2008 and, as a list MP, his potential move to the WTO would not trigger a by-election.