A powerful 7.1 magnitude earthquake struck the Philippine island of Luzon today, the US Geological Survey said, badly damaging a hospital and buildings in a northern province and sending strong tremors through the capital, Manila.

A hospital in Abra province was evacuated after the building partially collapsed following the quake, but there were no casualties reported, said officials.

"We are still experiencing aftershocks. We have received reports of damages to houses. But so far no casualties," said Mayor Rovelyn Villamor in the town of Lagangilang in Abra province.

"We don’t have a power supply because that’s automatically cut off due to danger," Villamor told DZRH radio.

The public information office of Abra province posted photographs on its Facebook page showing buildings badly damaged, with walls with huge cracks crumbling.

USGS said the earthquake's epicentre was about 11km east-southeast of the town of Dolores and occurred at a shallow depth of 10km.

"The focus of attention is on Abra and nearby provinces. This is a major earthquake. We expect strong aftershocks," Renato Solidum, director of the state seismology agency, told DZMM radio station.

Eric Singson, a congressman in the northern Ilocos Sur province, told DZMM radio station the quake had been felt strongly.

"The earthquake lasted 30 seconds or more. I thought my house would fall," said Singson.

"Now, we are trying to reach people .... Right now, there are aftershocks, so we are outside our home."

The quake was also felt in Manila and the city's metro rail systems were halted at rush hour after the quake, the transport ministry said.

The senate building in the capital was also evacuated, media reported.

- Reuters