Highway authorities used explosives to blast apart a 2,000 tonne boulder that closed part of a key highway for two weeks after rolling down a hill during heavy rains, a senior official said late yesterday.

"It was a success. We are cleaning up now. But we may need to use more explosives to blast other big boulders," a highway official told AFP on condition of anonymity.

The huge boulder landed in the centre of the eight-lane highway, forcing police to close the roadway. Some 60,000 vehicles use this particular stretch of highway daily.

Thousands of tonnes of rocks came crashing onto the expressway just north of the capital Kuala Lumpur early Wednesday. Crews are working round-the-clock to clear the debris.

The north-south highway links southern Johor state, neighbouring Singapore, to the northern Perlis state, bordering Thailand.

It is used by lorries to ferry goods to ports in the country and Singapore. - AFP