Foreign Secretary Jack Straw (search) said Monday that 159 Britons are thought to have been victims of the Asian tsunamis, in addition to the 40 British citizens confirmed as dead.

It was the first time the government has given an official estimate of the number of Britons who are thought to be missing and feared killed.

Straw said London's Metropolitan Police established a list of 159 British nationals who are "highly likely to have been involved as victims of the disaster."

He added that most of those were thought to have died in Thailand, although it was possible not all of them had perished. Forty-three British police officers have been sent to Thailand to help identify bodies thought to be those of Britons.

"Because of the scale and the nature of the disaster, and the fact that many of the bodies of the dead may sadly never be found, firm estimates of casualty figures remain difficult," Straw told a news conference.

So far, the Foreign Office has confirmed that 29 Britons died in Thailand, eight in Sri Lanka and three in the Maldives (search).

"It is tragically very probable that the number of confirmed British victims will continue to rise," Straw said.

He added that it was "almost certain" the government's 50 million pound (US$96 million) aid package for affected countries would rise to match the 60 million pounds (US$115 million) donated by the British public.

Straw refused to confirm reports that Prime Minister Tony Blair (search) was expected to return later Monday from his vacation in Egypt. Blair was already in Egypt when the tsunamis struck on Dec. 26.

The leader of the main opposition Conservative Party, Michael Howard (search), has said he would have come back from holiday if he had been in the prime minister's position.

But the foreign secretary rejected any suggestion Blair's absence had been a problem.

"The prime minister is kept in the closest possible touch with the Deputy Prime Minister [John Prescott], International Development Secretary Hilary Benn and myself throughout this," he said.

"Is there a single thing that the British government should have done that it hasn't done, notwithstanding the fact that the prime minister has been abroad? And the answer to that is no."