Bill English

He will be leading a delegation of New Zealand Pasifika community leaders, iwi and business representatives.

The Minister of Foreign Affairs Gerry Brownlee and the Minister for Pacific Peoples Alfred Ngaro will accompany the Prime Minister, alongside leaders and representatives of parties from across the House.

Mr English said that while in the Cook Islands he would meet with Prime Minister and Cabinet Ministers to discuss a range of regional and domestic matters.

It follows Mr Key's surprise resignation last week. Social housing minister Paula Bennett has been named as deputy prime minister.

The appointments were confirmed after a meeting of the National Party's caucus.

Mr English, currently finance minister and deputy prime minister, will be officially sworn in at Government House in Wellington later on Monday.

In a tweet, Mr English said he was "excited and humbled" to be elected.