Private cellular operators have asked the telecom regulator to approve the revised tariff packages offering Rs 0.50 per minute STD charges, saying delay in implementation would result in large-scale erosion of customer base.

"Because of predatory tariff packages of some of the operators, which are already available in the market, the subscriber base of cellular operators has already been eroded to a great extent and this will continue to erode every day in case we are not allowed to introduce the competitive package in the market," cellular operators said in a letter to Trai.

Earlier, Trai had asked leading companies including Bharti, IDEA and Hutch to continue with their existing tariff till it evaluated their packages relating to slashed STD, ISD and air-time charges.

Bharti, Hutch and IDEA had recently cut the airtime on mobile-to-mobile STD calls to just 50 paisa, while it completely waived the airtime for ISD calls.

The cell operators in their reply said that while their packages were out of competitive compulsions, they also complied with the Interconnect User Charge regulations.