An eight-year-old girl has been pulled alive from the wreckage of a collapsed building in Tainan, the fourth to be rescued on Monday, more than 60 hours after a powerful quake struck southern Taiwan.

Rescuers also saved the girl's aunt as they raced against time to find more than 100 residents buried deep in the ruins of the toppled Wei-guan Golden Dragon Building. 

Earlier on Monday, two more people - a man and a woman - were pulled from the rubble, as the official death toll rose to 38..

Local legislator Wang Ting-yu told reporters that the rescued woman, Tsao Wei-ling, was found shielded under the body of her dead husband. Their two-year-old son, who was also killed, was found lying nearby.

Rescuers also confirmed that the other survivor - a man called Li Tsung-tian - had been pulled out of the rubble.

Rescue efforts are focused on the wreckage of the 17-storey building, where 117 people are listed as missing.

More than 100 people were missing after a 6.4-magnitude earthquake struck southern Taiwan, authorities said [EPA]

Al Jazeera's Rob McBride, reporting from outside the collapsed building, said the rescue effort had reached a critical point.

"It has been three days, and it's understood that those stuck under the rubble and still alive won't be able to last longer without food and water.

"Lots of questions are being asked about how this building was constructed. There are a lot of stories floating around about the builder. You could almost say he is the most wanted man in Taiwan right now. Everyone is trying to find him," he said.

William Lai, the Tainan mayor, said Tsao and Li were the only signs of life at present, although rescuers were continuing to look for others.

"We have not given up on even the tiniest of possibilities," he told reporters.

Rescuers continued to scramble over the twisted wreckage of the building as numbed family members stood around, waiting for news of missing relatives.

READ MORE: Powerful earthquake rocks southern Taiwan

President-elect Tsai Ing-wen, who won the election last month, said there needed to be a "general sorting out" for old buildings to make sure they were able to cope with disasters such as earthquakes.

"There needs to be a continued strengthening of their ability to deal with disasters," she said during a visit in Tainan.

Outgoing president Ma Ying-jeou is also scheduled to visit.

Chinese President Xi Jinping conveyed condolences to the victims, state news agency Xinhua reported late on Sunday, and repeated Beijing's offer to provide help.

Source: Al Jazeera and agencies