International aid arrived into Sri Lanka on Wednesday as the death toll from the island's worst floods and landslides in well over a decade climbed to 202.

Thousands of Sri Lankan troops battled Monday to get relief supplies to nearly half a million people displaced by the island's worst flooding in well over a decade, which has killed 169 people.

Flooding and landslides killed at least 91 people and left another 110 missing in Sri Lanka as the monsoon set in Friday, dumping record rainfalls in many parts of the island, authorities said.

Sri Lanka has outlawed protests over Colombo's garbage crisis following rallies over the city's waste disposal after a landslide at a giant rubbish tip killed 32 people and destroyed 145 homes.

Sri Lanka on Wednesday ended the grim search for survivors five days after a huge garbage mountain collapsed onto a slum, killing 32 people and forcing the evacuation of hundreds of residents.

Sri Lanka has moved over 400 families to temporary shelters after tonnes of rotting garbage collapsed onto a slum on Friday, killing 26 people.

Attackers opened fire on a prison bus outside Colombo on Monday, killing five prisoners and two armed guards in the worst gang-related violence to hit Sri Lanka in decades.

Sri Lankan police have arrested an astrologer after his prediction that President Maithripala Sirisena would die last week proved to be wide of the mark.

Sri Lanka surpassed the world record for the tallest artificial Christmas tree Saturday despite building delays forcing organisers to prune the structure by almost half, an official said.

"This is a great victory for us and it will help us in the fiscal consolidation programme that the new government has started," Finance Minister Ravi Karunanayake said.

Sri Lanka's President Maithripala Sirisena has asked Donald Trump to pressure the UN Human Rights Council to drop war crimes allegations against the country's troops.

UN chief Ban Ki-moon Friday urged Sri Lanka to speed up returning land to war-battered minority Tamils and reduce the army's presence in their areas to help reconciliation after decades of ethnic bloodshed.