Thai soldiers and government workers in Bangkok are racing to reinforce the capital's northern flood defenses with 1 million more sandbags.

Officials said early Monday that the flood threat to the city had passed. But authorities have discovered new weaknesses in barriers erected north of the city, where an industrial estate was inundated Monday. They say they have until Wednesday evening to shore up the flood walls.

The flooding has also affected millions of people in Cambodia, Laos and Vietnam. More than 300 people have died in Thailand, where the flooding is described as the worst in 50 years. Vietnam on Tuesday said the death toll there has reached 55.

Government officials were on the front lines north of Bangkok Tuesday, urging soldiers and workers to improve their efforts.

An official told workers in one location they needed to make the barrier higher.

Government officials say the impact of the flooding on the nation's economic growth will be severe.

Commerce Minister Passagorn Pousiri said he was unwilling to estimate the exact cost, but economists put the figure as high as $7 billion.

Cambodian officials say their economy will also suffer, with growth expected to be reduced this year by 6 to 7 percent.

A Chinese embassy official was in hard-hit areas of Cambodia Tuesday, helping to distribute relief supplies.

He Le Ping said China and Cambodia are good friends and must help one another in times of hardship.

Fifty-two-year-old Hieng Lay was among the lucky recipients of the Chinese aid.

He said his family needs rice, medicine and cooking oil.