Almost 25,000 people have been evacuated to makeshift camps after floods wreaked havoc in eastern Myanmar, according to an official, as relief teams struggle to reach remote areas inundated by water.

Flood waters have risen dramatically after several days of heavy rain in Karen state, forcing thousands to flee to nearly 80 relief camps, Chum Hre, director of the social welfare, relief and resettlement department, told AFP news agency on Wednesday.

"Altogether 24,499 flood victims have been evacuated" in Karen state, he said, adding that hundreds more had been displaced in Mon and Rakhine states.

"It is very difficult to reach some of the disaster-hit places because of the bad weather and landslides," Hre said.

He said helicopters had been deployed.

Thai flooding

Heavy rains also inundated areas across the border in Thailand. Seven Thai provinces remained flooded on Wednesday, the country's interior ministry said in its daily update.

Three people have died since Monday after they were hit by trees felled by fast-moving water, it added.

In Thailand's western town of Mae Sot, which borders the flood-hit area of Myanmar, waters have receded in the town centre but remain high in outlying areas, especially near the frontier checkpoint.

"The situation has returned to normal in Mae Sot city," Pramote Chantasri, of Mae Sot City Municipality told AFP.

"The worst was on Monday after four days of heavy rain in the mountains," he said, adding the bridge between the two countries remains open.

Monsoon cycle

Parts of Thailand and Myanmar are inundated each year during the monsoon period, which ends in October.

Deadly floods in 2011 left more than 800 people dead in Thailand, inundating swathes of the country for months, deluging parts of the capital and taking a heavy toll on the country's lucrative manufacturing industry.

Al Jazeera meteorologist Richard Angwin said: “Rainfall figures are not readily available for Myanmar but in a typical year, the southwesterly monsoon produces staggeringly large amounts of rainfall."

"Between June and August, when the rain is at its peak, Yangon will typically see around 1700mm of rain.

"If the rainfall being reported in neighbouring Thailand is anything to go by, this is not a typical monsoon season.

"Across much of South Asia this year’s rains have been up by as much as 50 percent compared with a typical year.

"With the dry season not expected to return until late October, Myanmar could be in for several months of disruptive weather.”

Source: Al Jazeera and agencies