Thai authorities said they have arrested a Chinese executive at a company that was building a Bangkok skyscraper which collapsed in a major earthquake, leaving dozens dead.

The 30-storey tower was reduced to an immense pile of rubble when a 7.7-magnitude quake struck neighboring Myanmar last month, killing 47 people at the construction site and leaving another 47 missing.

Justice Minister Tawee Sodsong told a news conference Saturday that a Thai court had issued arrest warrants for four individuals, including three Thai nationals, at China Railway No.10 for breaching the Foreign Business Act.

The Department of Special Investigation, which is under the justice ministry, said in a statement Saturday that one of the four had been arrested — a Chinese "company representative" who they named as Zhang. 

China Railway No.10 was part of a joint venture with an Italian-Thai firm to build the State Audit Office tower before its collapse.

Zhang is listed as a 49-percent shareholder in the firm, while the three Thai citizens have a 51-percent stake in the company. 

But Tawee told journalists that "we have evidence... that the three Thais were holding shares for other foreign independents".

The Foreign Business Act says that foreigners may hold no more than 49 percent of shares in a company.

Separately, Tawee said several investigations related to the collapse were ongoing, including over the possibility of bid rigging and the use of fake signatures of engineers in construction supervisor contracts.

Earlier this month Thai safety officials said testing of steel rebars — struts used to reinforce concrete — from the site has found that some of the metal used was substandard.

The skyscraper was the only major building in the capital to fall in the catastrophic March 28 earthquake that has killed more than 3,700 people in Thailand and neighboring Myanmar.