New Zealand's next ambassador to the United States will be Rosemary Banks who will resume her diplomatic career with the plum appointment.

She will replace Tim Groser, a former diplomat who became a National Party politician and Trade Minister.

Banks, aged 67, has previously been ambassador to France and Portugal, and New Zealand's Permanent Representative to the United Nations in New York.

She was part of a team who worked closely on the bid for former Prime Minister Helen Clark to become United Nations Secretary General.

Banks is currently a Crown negotiator in the Treaty of Waitangi settlement process, a member of the council of the University of Canterbury, and a senior adjunct fellow in the department of political science.

Foreign Minister Winston Peters said Banks was a highly experienced diplomat and public servant who would be a consummate professional in representing New Zealand's interests in Washington.

He also acknowledged Tim Groser who left politics in 2016 to take up the job.

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"He has been a strong advocate for New Zealand and has been successful in cementing the relationship between our two countries," Peters said.

Peters has had a longstanding opposition to political appointments to diplomatic posts - although he is expected to replace outgoing High Commissioner to Australia Chris Seed with former veteran politician Dame Annette King.

The post has previously held by former Prime Ministers Jim Bolger and Mike Moore.

Banks is the first woman to hold the post.

She had been among those tipped as a potential candidate for Foreign Affairs chief executive, which becomes vacant in February.