Prime Minister Helen Clark will cut short an overseas holiday and return home early next week following the devastation from South Asia's tsunami.

"In these circumstances I think the best place for me to be is at home," she said in a statement today.

The decision comes with it being thought up to three more New Zealanders were killed in tsunami-affected Southern Thailand. A total of 64 New Zealanders remained unaccounted for in the area this morning.

She said she had recently spoken to, and extended her sympathies to leaders of several countries caught up in the disaster, including the Indonesian president, who had mentioned his appreciation of assistance being provided by New Zealand.

"My thoughts are with all New Zealand families who have received no news of their loved ones caught up in this tragedy. As the days go by their concern deepens, as does mine," Helen Clark said.

She was in daily contact with Foreign Minister Phil Goff and other key staff and thanked those working around the clock in response to the disaster.

"I also thank all New Zealanders who have donated generously to appeals for relief funds."

New Zealand would play its part in the international reconstruction effort following the immediate emergency response, Ms Clark said.