The Philippines put troops on alert on Wednesday and prepared food and medical supplies as it warned residents and tourists along its eastern coast to be ready for a super typhoon expected to land sometime in the next 72 hours.

Typhoon Maysak, initially a top-rated category 5 typhoon, weakened slightly as it moved towards the Philippines, hurtling over the Pacific Ocean with winds gusting up to 225 kph (140 mph), the weather bureau said.

It is expected to further weaken once it hits the central or northern parts of the main Philippine island of Luzon on Saturday or Sunday, the agency said, as the Philippines celebrates the Easter long weekend.

"This is very strong and it will maintain its strength as it nears, although we expect that the typhoon will weaken," Esperanza Cayanan, an officer at the weather bureau, said in a televised briefing.

"But this will still be typhoon intensity so it will bring strong winds when it makes landfall on the eastern coast," Cayanan said.

British-based Tropical Storm Risk said Maysak would likely weaken to a category 2 typhoon, with maximum winds of up to 175 kph (110 mph), when it hits land.

The typhoon could damage rice and corn crops in central and northern areas of the Philippines, although damage is likely to be minimal because the major harvest of the national staple rice was finished around February.

Alexander Pama, executive director of the national disaster agency, said the biggest challenge for authorities would be keeping foreign and Filipino tourists travelling to northern provinces for the weekend safe when Maysak makes landfall.

Thousands of Filipinos have already begun travelling to the provinces and popular tourist spots before the Easter weekend.

Maysak is not expected to make landfall where another category 5 typhoon, Haiyan, struck more than a year ago, leaving nearly 8000 dead or missing. – Reuters