PHUKET, Jan 17: Sweden's Prime Minister Goeran Persson said on Monday Thailand should explain why its seismologists failed to warn anyone of last month's killer tsunami if it wants tourists to return.

Goeran Persson, who was visiting the kingdom with his counterparts from Norway and Finland, also said hotels and resorts devastated by the waves needed to be better built in order to withstand such punishing natural forces in the future.

More than 5,300 people are confirmed dead in south west Thailand, about half of them foreigners holidaying in resort towns like Khao Lak, where fishing villages and luxury hotels alike were devastated by the December 26 waves.

Fifty-two Swedes have been confirmed dead throughout the region while 893 remain missing. Mr Persson said he feared the number of Swedish dead might eventually "come close to 1,000".

"I ... expressed direct to the Thai authorities that we want to see an investigation about the warning for the catastrophe," which began with a massive earthquake off Sumatra's west coast, Persson told reporters on this resort island amid a tour of the region.

"The earthquake came a long time before the tsunami. The tsunami hit the shores and killed thousands of people. Why wasn't it a warning, because there was knowledge about the tsunami."

Mr Persson's remarks were among the toughest the Thai government has received from the stream of foreign dignitaries who have passed through the country since the tsunami.

The Swedish leader has faced stiff criticism at home over his government's response to the tsunami, which struck as 20,000 Swedes were vacationing in the region.

His foreign minister Laila Freivalds has been blasted for going to the theatre the evening of Dec 26, as news was coming in of thousands of missing Swedes. No emergency help was sent to the affected regions for several days.

The Thai government announced last month it would set up an inquiry into why the public was not alerted to the waves. Prime Minister Thaksin Shinawatra transferred the head of the meteorology department amid the inquiry.

The Nation newspaper had reported that meteorological department officials held a meeting chaired by director-general Supharerk Tansrirat tanawong minutes after the quake struck at 7:58 am local time.

It quoted Supharerk as saying they did not expect a tidal wave since one had not hit Thailand for 300 years. Thailand is leading the push for a tsunami early warning system for the Indian Ocean similar to that in place in the Pacific.

After touring scenes of devastation in Khao Lak north of Phuket, Persson called for a tightening of building codes when reconstruction of beachfront properties begins. -AFP