MANILA:  Philippine forecasters have warned fishing boats not to venture out to sea and commercial ships to watch out for big waves as a powerful typhoon roars off the country's northeastern coast.

Government forecaster Aldzar Aurelio said Thursday that fast-moving Typhoon Nepartak would not likely hit land but would intensify seasonal southwest monsoon rains, which could spark thunderstorms and flash floods on the main northern Luzon island. Some domestic flights have been canceled in the region.

Aurelio says Nepartak was blowing over the Philippine Sea about 235 kilometres (146 miles) northeast of Batanes province with sustained winds of 220 kilometres (136 miles) per hour and gusts of 255 kph (158 mph).

The typhoon can still gain strength and will start to blow away from the Philippines Friday and head toward Taiwan.