New Zealand officials have apologised to Prime Minister Julia Gillard after a driver refused to let her on to a bus with other leaders during the Pacific Islands forum in Auckland last week, telling her instead to get on the spouses' bus.

A spokesman for NZ Internal Affairs confirmed the incident and said the apology was offered as soon as officials were made aware of it.

Bus gaffe ... Julia Gillard with New Zealand Prime Minister John Key at the opening of the annual Pacific Islands Forum in Auckland on September 7. Credit:AFP

The driver concerned had not been used again during the forum. He was employed by a company that ferried the leaders around Auckland under contract to the Department of Internal Affairs.

The incident happened when foreign leaders and their partners were being driven from Sky City Grand Hotel to the waterfront in two buses last Thursday.