Tonga's international airport is busy as passengers check in for the first flights out of the country since a riot erupted in the capital last Thursday.
Airlines had suspended flights because of concerns of safety.
A joint New Zealand/Australia defence force unit secured the airport.
The Prime Minister says New Zealand isn't taking sides in the dispute and its offer of help is about supporting a proper process of constitutional reform in Tonga.
Helen Clark says New Zealand remains ready to help move forward the discussions in Tonga towards democratic reforms.
