Sky News, which did not cite a source, said SMRT is at the early stages of considering an offer.

SMRT, which operates Singapore subway lines and has bus and taxi services, did not confirm or deny the report.

"SMRT constantly looks out for investment opportunities that contribute to sustainable growth for our stakeholders," Benny Lim, its managing director for roads, said in an emailed response.

Private equity firm Carlyle Group, which bought a significant stake in Addison Lee last year, did not immediately respond to an email seeking comment.

(Reporting by Aradhana Aravindan; Editing by Richard Borsuk)

Stocks treated in this article : SMRT Corporation Ltd., The Carlyle Group LP