New Delhi, Sep 3 - The wait for number portability, which will enable subscribers to switch telecom operators without getting their phone numbers changed, has got longer with the government Thursday extending the implementation deadline from Sep 20 to Dec 31.

'The implementation of first phase of the mobile number portability (MNP), in metro and category A service area has been extended to December 31, 2009,' an official statement said.

MNP allows users to switch operators without changing numbers.

As a result, the MNP service is likely to be available by end of this year in Delhi, Mumbai, Kolkata, Maharashtra, Gujarat, Andhra Pradesh, Tamil Nadu including Karnataka, and Chennai service areas.

'The Department of Telecommunication has extended the date of implementation in view of time and efforts required to customise and upgrade the existing networks for enabling them to provide MNP service,' the statement added.