Prime Minister John says the National Party will have to work hard to retain the seat of Napier, when Chris Tremain MP retires next year.
Mr Tremain will not contest the next election because of family reasons and because he wants to pursue a career in business.
He is the Minister of Internal Affairs, Minister of Local Government and Associate Minister of Tourism.
Mr Key says Mr Tremain has done a great job, particularly in securing the Napier seat for National in 2005, for the first time in about 50 years.
He said there will be some more retirements at next year's election, but would not be any more specific.