Communication Minister A Raja said on Friday that the mobile number portability, which would allow users to switch service providers without having to change their phone numbers, would be launched in the first week of May.

In the first leg, it would be launched in Chennai and Bangalore, said Raja without commenting on the roll out thereafter in other parts of the country.

"You can retain your number whatever be the company in which you are having service".

But Department of Telecom officials later said it is expected to be launched in other places soon after reviewing the "experience" in the these two cities.

Speaking at the launch of 3G services in Karnataka circle by BSNL, he said the government had taken a policy decision to launch MNP by this March, but it was not able to get security clearance for the imported devices.