Heavy monsoon rains in Myanmar have forced tens of thousands of people to seek shelter in emergency camps and submerged vast swathes of cropland, officials said on Monday.

A man rows a boat past partially-submerged houses in a village outside Pathein, in the Irrawaddy delta region of Myanmar, on August 22.

"We have been giving necessary assistance such as rice and household kits to the flood victims," the ministry's director general Soe Aung told AFP.

"Some people went back to their homes as the water level subsided."

The worst-affected southwestern delta region -- which was devastated by a cyclone in 2008 that left 138,000 people dead or missing -- has been lashed by the heaviest rains in eight years, according to the authorities.

No fatalities have been reported in the delta but two men, aged 25 and 35, died in flooding in Lashio in eastern Shan State earlier this month, according to the authorities.

More than 136,000 acres (54,400 hectares) of farmland have been inundated by the floods, which began in late July in Shan and spread to other parts of the country, Soe Aung said.

Myanmar's former military regime, which was replaced by a nominally civilian government last year, faced international criticism for its response to Cyclone Nargis in 2008, when it was accused of blocking emergency aid and initially refusing to grant access to humanitarian workers and supplies.