The Chinese mainland has offered to help Taiwan following the deadly earthquake that jolted the south of the island early on Saturday morning.

The mainland's Association for Relations Across the Taiwan Straits (ARATS) has been in contact with Taiwan's Straits Exchange Foundation (SEF) since 6 a.m., around two hours after the quake struck near the city of Tainan, said Ma Xiaoguang, spokesperson for the State Council's Taiwan Affairs Office.

The ARATS has sent a letter to the SEF offering rescue assistance if needed.

Ma also expressed concern and condolences for those who have suffered in the quake.

The quake damaged several buildings, causing the collapse of at least one, trapping hundreds of residents and leaving two dead, according to local media reports.

The mainland earthquake monitoring center put the scale of the quake at 6.7-magnitude.