JAKARTA (Reuters) - A consortium building a long-awaited mass rapid transit (MRT) railway in the Indonesian capital of Jakarta has replaced two top officials, a representative said on Wednesday, amid doubts the US$3 billion dollar project can be completed on time.

A consortium of Indonesian and Japanese firms, including Obayashi Corp, Shimizu Corp and Sumitomo Mitsui Construction Co Ltd, is building the MRT in the city of 10 million people, which is among the world's most traffic-logged.

"The chief executive and operational director have been changed," said Mr Tubagus Hikmatullah, the corporate secretary of PT MRT, but he declined to elaborate on the reason.

The city governor's office did not respond to a request for comment.

Media reported that the changes followed an announcement by the old management of a delay until 2019 in the opening of the project's first, US$1.7 billion phase, and complaints over land acquisition.

Delayed repeatedly for more than 20 years, the project was finally launched in 2013, with the first line originally scheduled to have been opened in 2018.