Heavy rain said to be the worst in three years triggered flash floods submerging streets in Phnom Penh, Cambodia.

Footage shows locals wading through the deluge, which entered shops and rendered roads impassable to vehicles on July 3. Some cars were also seen floating in the rubbish-filled water.

Sam Piseth, Phnom Penh Department of Public Works and Transport Director, described the downpour as the 'heaviest rainfall in three years' and urged residents to clear the storm drains of garbage.

Around 14 districts were flooded in Phnom Penh, local media reported.

Authorities said they have deployed water pumps to ease the flooding.

Cambodia and neighbouring countries in Southeast Asia are approaching their annual monsoon rainy season which sees soaring temperatures followed by powerful rain storms in the afternoon leading to widespread flash floods.