BEIJING - Coastal regions are on yellow alert with giant waves expected as two typhoons move closer to the mainland.

China's National Marine Environmental Forecasting Center raised the alert level on Friday.

In the morning, "Tembin" -- the 14th typhoon of the year -- moved towards the northeast of the South China Sea and is expected to roll monster waves of between five and eight meters in the afternoon. It whirled its way through the southernmost tip of Taiwan at 5:15 am, according to a warning statement from the center.

The center uses a four-tier color-coded heat warning system, with red being the most severe, followed by orange, yellow and blue.

Waves off the coasts of Fujian and Guangdong provinces are expected to be as high as 3.5 meters, said the statement.

Fishing boats in those areas have been warned to take safety measures ahead of the approaching surges of water.

Meanwhile, the 15th typhoon of the year -- "Bolaven" -- is about 1,570 km east of China's coast. It is also moving closer with a speed approaching 20 km/h and is constantly gaining power.

"Bolaven" was predicted to wreck havoc off and along the northeast coast of the country from Sunday to next Wednesday, bringing wild seas as high as 12 meters in the East China Sea and the Bohai Sea.

The center said that the two typhoons will exert more influence as they grow.

Earlier this month, dual-typhoons "Damrey" and "Saola" left eight people dead and forced the evacuation of about 1.3 million residents in coastal regions as of August 5.