DAVAO CITY, the Philippines - Hundreds of passengers have been stranded as sea and air travel have been suspended in southern Philippines due to the upcoming tropical storm Son-Tinh, authorities said on Wednesday.

Local and disaster officials were also on alert as the weather disturbance intensified and hovered over northern the Mindanao region, said Blanche Gobenciong, regional disaster officer for the Caraga region.

At 7 am on Wednesday, tropical storm Son-Tinh was estimated based on satellite and surface data at 140 kilometers east of the Siargao island in the Caraga region, the Philippine Atmospheric Geophysical and Astronomical Services Administration said in its 8 am bulletin.

With maximum sustained winds of 65 kilometers per hour near the center, and gustiness of up to 85 kph, the administration said the storm is moving west-northwest at a speed of 15 kph.

Gobenciong said due to the approaching storm, domestic carrier Cebu Pacific has cancelled its 6:45 am flight from the regional center Butuan City to Davao.

"The Coast Guard also announced the suspension of sea travel from Siargao and nearby island of Dinagat, as well as from Surigao City to Cebu and Leyte (in the Visayas)," Gobenciong told Xinhua by text message.

Public storm signal number 2 has been hoisted over the region and in the eastern Philippine province of Southern Leyte. The authorities have warned winds with speed of 60-100 kph are expected in the next 24 hours.

Although the regional disaster office has yet to receive reports about any untoward incident related to the storm, Gobenciong said the Caraga region has been put on alert.

The Philippines sits in the so-called Pacific Typhoon Belt, with at least 21 storms visiting the archipelago annually.