Taiwanese officials have arrested the developer of a high-rise building that collapsed in last week's earthquake.

Lin Ming-hui, the builder of the Wei-guan Golden Dragon Building, which was responsible for most of the casualties in the earthquake, has been charged with negligent homicide, prosecutors have said.

While authorities have confirmed the death of about 40 people, another 100 are still missing, feared buried under the rubble of the 17-storye residential building.

Two of the employees of Lin have also been detained and taken for questioning in Tainan city, officials said.

Earlier, Tainan mayor had said an inquiry into possible building norms violations was underway.

"I've contacted judicial units and prosecutors have formally launched an investigation," Tainan mayor William Lai had said even as rescue efforts were going ahead.

The Asia One daily had reported, citing local media, that there were doubts about the construction quality the high-rise that collapsed. Reports said the builder had gone out of business and there were questions about the quality of building materials used.

The straits Times reported that witnesses saw large, rectangular, commercial metal cans were packed inside wall cavities, suggesting these were used as building material.

It was also suspected that polystyrene was used to support beams, mixed in with concrete.

"Locals never bought condos there because the builders did not have a good reputation," a local resident said.