US-based ride-hailing service Uber Technologies Inc merges its China business with rival Didi Chuxing. [Photo: news.gmw.cn]

China's Commerce Ministry says it has launched an antitrust probe into the mega merger between the top two ride-hailing service providers Didi Chuxing and Uber China.

The ministry says it had not received an application from Didi or Uber on their merger deal.

The authority has held two meetings with Didi operators ,and required the company to explain why it failed to do so, and hand in necessary documents.

Didi announced at the beginning of last month its decision to acquire Uber's China operations.

The deal was completed on August 2, creating a ride-sharing titan estimated to take about 90 percent of the market.

According to antitrust regulations in China, companies that plan to merge need to file an application to the authorities if their combined revenue exceeded 2 billion yuan in the previous year.

Even if companies' revenues didn't reach the threshold, a probe can also be conducted if there was evidence suggesting a potential monopoly.