PM 'Ulukalala Lavaka Ata resigned at the weekend, six months after strikes and protests led to calls for the royal family to allow more democracy.

The new acting Prime Minister, Fred Sevele, is one of only a few politicians elected rather than appointed by the king.

King Taufa'ahau Tupou, 87, is reported to be in New Zealand for medical care.

Prime ministers of Tonga, a group of coral islands 2,000km (1,200 miles) north of New Zealand, have traditionally been drawn from the royal family or nobility.

Mr Sevele said his appointment showed the country's rulers were changing.

"It indicates their willingness and their readiness to look at the ability of people," he said, according to broadcaster Radio Australia.

Mr Sevele is a long-term advocate of more democracy for Tonga's 106,000 people.