Senior career diplomat John Wood is understood to be the next ambassador to Washington, replacing Jim Bolger when the former prime minister's term ends this year.

Mr Wood, a deputy secretary in the Ministry of Foreign Affairs, has already served one term as ambassador in Washington, during the 1990s.

Because of his experience in trade and Apec matters, Mr Wood's return is thought to signal New Zealand's determination to strike a free-trade pact with the United States.