India ordered a halt in December to operations of all unregistered web-based taxi companies after a female passenger reported she had been raped in New Delhi by a driver contracted to U.S. cab company Uber.

Uber halted operations after the complaint but resumed in January after applying for a radio-taxi licence. Ola, backed by Japan's SoftBank Corp, continued operations.

Delhi's government transport department said in separate, similarly-worded letters to local units of Uber and Ola that continuing their taxi services would contravene a December order by the government.

Rules set by Delhi's transport department in December require companies operating taxi-hailing apps to install emergency buttons in their cabs and have tracking devices.

"In order to process your application further, I am directed to seek a sworn affidavit declaring therein that you are complying with the ban order imposed upon your company in letter and spirit," an official from the transport department wrote.

Spokesmen for Uber and Ola were not immediately available for comment.

(Reporting by Aditya Kalra; Writing by Nidhi Verma; Editing by Ruth Pitchford)