Super typhoon Megi is expected to enter the South China Sea Tuesday, meteorological authorities said Monday, as torrential rains have already forced the evacuation of almost 140,000 people in the southern island province of Hainan.

Possibly the strongest typhoon to hit China this year, Megi, which means "catfish" in Korean, is heading for northern Luzon island, the Philippines, at a speed of 20 km per hour, China's National Meteorological Center (NMC) said in a statement. It is expected to reach Luzon either Monday afternoon or evening.

The 13th typhoon of the year, Megi is packing winds of up to 260 km per hour, making it the strongest typhoon to appear in the northwest Pacific since 1990 and the strongest typhoon of the year worldwide, the NMC said.

It is forecast to enter the eastern part of the South China Sea Tuesday morning, bringing strong winds and rain.

The center has issued warnings for vessels in the area.

Meanwhile, the southern island province of Hainan Monday continued to battle the torrential rain that began lashing the island Friday.

So far, almost 1.3 million people have been affected and 140,000 have been forced to evacuate low-lying areas.

Strong rains have inundated villages, damaged house, flooded crops and forced 84 primary and middle schools in the provincial capital, Haikou, to suspend classes.

Direct economic losses are estimated at about 1.52 billion yuan (232 million U.S. dollars), the Ministry of Civil Affairs said Monday.

The ministry has dispatched a team to Hainan to oversee the disaster relief operations.