Foreign Minister Murray McCully will stand in for Prime Minister John Key at the Commonwealth Heads of Government Meeting in Perth this week.
Mr McCully was leaving for Australia on Tuesday to attend the Foreign Ministers' meetings, before representing the Prime Minister at the Leaders' meetings.
He will brief Commonwealth Leaders on the outcome of the recent Pacific Islands Forum meeting in Auckland.
The Commonwealth meeting is one of three international gatherings Mr Key will not attend because of the election campaign.
In November, Deputy Prime Minister, Bill English will represent New Zealand at an APEC leaders' meeting in Hawaii, and Mr McCully will attend an ASEAN meeting in Bali.
