Finance Minister and Deputy Prime Minister Bill English is to give up his Clutha-Southland seat at the next election and stand as a list candidate.
"This afternoon I met with my electorate committee in Gore to inform them of my decision," he said in a statement.
"Representing one of New Zealand's largest electorates has required considerable travel and time away from my family, particularly since becoming a minister. I have therefore decided that it is a good time to strike a better balance between my family and government commitments."
Mr English won the seat when it was called Wallace in 1990 and has held it since.
"I will continue to take a strong interest in issues affecting Southland and Otago and I'm confident the National Party will provide strong representation for the area into the future," Mr English said.