(AFP) - Prime Minister Dr Mahathir Mohamad has blamed poor development planning for freak floods that hit capital city Kuala Lumpur Thursday, killing two people and leaving thousands stranded.

Mahathir said Saturday the government would need to spend a huge sum to deal with problems such as squatter settlements to overcome flash floods.

"The designs of development projects are not very good but it is a little late to do anything unless we are prepared to spend large sums and also tackle the squatter problem," he was quoted as saying by the Bernama news agency on his return from Dubai.

Heavy downpour Thursday wreaked havoc in Kuala Lumpur, with thousands of vehicles and main roads submerged, bus and rail services disrupted and massive traffic jams.

A victim was electrocuted to death while another drowned. Authorities have mounted a massive operation to clear the city of mud and debris.

The city drainage and irrigation department has cited poorly maintained drains and an overflowing river for the floods.

Asked about a proposal by Works Minister S Samy Vellu that those throwing rubbish into rivers be jailed, Mahathir said the government would be accused of being inconsiderate if it did so.

The World Wide Fund for Nature, Malaysia, said the floods showed the country faced serious environmental problems. It said uncontrolled land clearing for development in the highlands was part of the problem.