A Philippines' government website dedicated to the prevention of national disasters has been hacked hours before a powerful typhoon was expected to hit the southeast Asian country.

Cyber pirates infiltrated the website of Dina, a new web service by the National Disaster Risk Reduction and Management Council, and redirected visitors to a porn website.

"A server where we upload was hacked," said council executive director Eduardo del Rosario. The website is still not accessible.

Del Rosario said the local branch of hacktivist group Anonymous could have been behind the disruption, PhilStar newspaper reported.

Anonymous Philippines said that it had attacked several government websites as part of a global protest against internet censorship and corruption.

The website was hacked on the very same day it was launched. It is supposed to provide Filipinos with real-time information about natural threats including cyclones, tsunami, floods, landslides and fires, as well as safety advices on how to prepare and face the disasters.

"It would educate the general public on disaster preparedness, through these visual aids our people will be able to know what to do before, during and after the advent of a hazard or emergency," Del Rosario told the Philippine Daily Inquirer.

Typhoon Haiyan, locally known as Yolanda, was making its way towards the central Philippines. It was expected to make landfall on Friday.

The typhoon was over the Pacific Ocean, some 900km east of the city of Hinatuan on the southern island of Mindanao, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said.

With wind speeds of 195km/h gusting up to 230km/h Yolanda was moving northwest at 30km/h.

The government said evacuation centres and emergency relief resources, including more than 80,000 family food packs, had been prepared.

Schools have been closed in the provinces of Cebu, Bohol and Albay while civil defence forces were on alert in metropolitan Manila and other provinces.

typhoon Yolanda
The Philippines coast guard posted a photo of its preparations for typhoon Yolanda (Twitter)