SHANGHAI (Reuters) - The authorities in China's south-western city of Chengdu visited the offices of Uber on Wednesday as part of a new investigation into the online taxi-hailing service, a spokesman for Chengdu's Transportation Commission said.

The visit is the second made by the authorities to Uber's China offices in the last week. The official Xinhua news agency said on Friday that Guangzhou authorities raided Uber's office there on suspicion of an "unlicensed operation". "A few of our departments visited Uber's offices to conduct interviews or an investigation," the spokesman, who gave only her surname, said on Thursday.

Ms Ren said she did not know the details of the investigation.

A spokesman for Uber in China said the visit was routine, citing a statement from the Transport Committee of Chengdu quoted by Chinese media. She did not provide more details. "There are no disruptions to the Uber platform and it's business as usual," she said in a statement.

Uber, which has been valued at an estimated US$40 billion (S$53 billion), is a comparative latecomer in China, where the number of mobile taxi-hailing app users is forecast to triple to 45 million by 2015 from 2013, according to Chinese research firm iResearch.

Domestic firms Kuaidi Dache and Didi Dache, backed by tech giants Alibaba Group Holding and Tencent Holdings respectively, have 90 per cent of the market sewn up. The two said in February that they would merge.