New Delhi, Nov 30 (IANS): Telecom service provider Idea Cellular has gained the maximum number of subscribers from other companies via the mobile number portability (MNP) route reporting a net gain of 15.72 lakh users as on Nov 15, the communications ministry said Wednesday.

Idea was followed by Vodafone and Bharti Airtel who saw net gains of 12.06 lakh and 2.95 lakh customers, respectively, Communications Minister Kapil Sibal said in a written reply in the Lok Sabha.

The minister also said that show-cause notices had been issued to companies which had not honoured porting requests.

"Wherever violations of MNP regulations and directions were observed, TRAI (Telecom Regulatory Authority of India) issued show-cause notices to the concerned service providers," said Sibal in a written reply.

"So far, the show cause (notices) have been issued to the following service providers: Bharti Airtel, Idea, Loop, Reliance and Vodafone," he added.

The minister said the regulator is also considering taking legal action against the firms which violated provisions of MNP.

"The replies received from the service providers have been examined and in the cases where TRAI reached the conclusion that the service providers have violated the provisions of MNP regulations and directions, TRAI is in the process of taking legal action."