WELLINGTON, Dec. 5 (Xinhua) -- New Zealand Prime Minister John Key on Monday shocked the nation and his Cabinet by announcing his resignation after eight years as the head of one of the most popular governments in recent history.

Key, who led his center-right National Party to three successive general election victories, said in a statement that he would not lead his party into a fourth term in next year's election.

His voice audibly shaking, Key said he had informed the Cabinet the same morning.

He cited family reasons for his resignation, saying the post had required great sacrifices "from those who are dearest to me."

He said his wife Bronagh had endured "many lonely nights" and his two children had been put under "extraordinary levels of intrusion."