Tonga's Prime Minister Fred Sevele has defended the lavish festivities marking the royal coronation this week.
"I, on behalf of the government, on behalf of the great majority of Tongans, make no apologies," Mr Sevele said, according to AP news agency.
Officials say some 5.7m Tongan dollars (US$2.5m) are being spent, in a country where poverty is widespread.
Hundreds of dignitaries are arriving to see King George Tupou V enthroned in a Christian ceremony on Friday.
The king, 60, was given roasted pig and kava, a mild narcotic drink, to mark his coronation in a traditional ceremony on Wednesday.
On Tonga's main island, Tongatapu, buildings and fences are decorated in bunting in the national colours, red and white. Hundreds of banners congratulating the king have been hung across roads.
Thousands of visitors arrived in Tonga on Thursday ahead of the main event on Friday.
These visitors included overseas Tongans and hundreds of dignitaries, including other royals such as Britain's Duke and Duchess of Gloucester, the Crown Prince of Japan and Princess Sirindhorn of Thailand.
There will also be many South Pacific royals.
Prime Minister Sevele defended the lavish nature of the celebrations, saying they were part of Tongan custom in Polynesia's last remaining monarchy.
Officials also pointed out that guests were likely to spend large amounts of money during their stay.
The king switched his woven mat skirt worn in Wednesday's traditional ceremony for a black tunic and military medals at a dinner for dignitaries on Thursday evening.
He will defy the muggy weather on Friday to don a scarlet velvet robe with an ermine trim.
He still rules over a semi-feudal political system where he and nobles decide the make-up of the cabinet and parliament.
But he has said he supports reforms, scheduled for 2010, in which most seats in the country's parliament will become popularly elected.
The promised reforms will follow destructive riots in the capital, Nuku'alofa, in 2006.