"As High Commissioner Dame Annette will be working on one of New Zealand's most significant relationships," he said.
"The transTasman bond is exceptionally strong, however the relationship is not something we take for granted, and the new High Commissioner will be tasked with keeping the connections strong."
Peters said the appointment is notable because Dame Annette is a former MP on a diplomatic posting.
"In this sense, she is an exception. Of the 25 Heads of Mission, appointments announced this year all have been career diplomats."
King stepped down as deputy leader for Jacinda Ardern in March last year and retired from politics at last year's election, holding the record as New Zealand's longest-serving woman MP.
She was a popular Member of Parliament, maintaining good relationships across the House.
The Government has already deployed King in a diplomatic role, sending her to Brussels last month as the Prime Minister's special envoy to the Asia Europe summit.
She held meetings there with European Parliament MPs about New Zealand's free trade negotiations with the EU.
In the past year, King has chaired the EQC. She was made a dame in the 2018 New Year's Honours list.
King was first elected to Parliament in 1984 and has held a range of portfolios including Health, Justice, Police and Transport.
Peters has been a strong critic of MPs becoming diplomats but has not opposed all such appointments. He says they should be made in exceptional cases.