Taking a strong exception to some private telecom operators disguising international calls on their networks as local ones, causing a revenue loss to the government, the Supreme Court today said such firms should not be allowed to go free just by payment of some fine.

Hearing a petition by BSNL against Reliance Communication (RCOM), the court said this is a serious matter and one should not walk away by paying some penalty only.

State-owned BSNL is having a dispute over interconnection charges for international calls made from RCom's network and shown as local calls by tampering caller line identification.

BSNL had raised a bill for about Rs 90 crore for the period during 2004-05 against Reliance Communication, which was at that time was owned by Mukesh Ambani as Reliance Infocom. The company was given to Anil Amabni in 2006 as part of the division of Reliance empire.

A bench headed by the Chief Justice S H Kapadia said that tampering of Caller Line Identification (CLI) was a serious issue and one should not walk away by paying some penalty only.

"...This arrangement should stop. This is a serious matter. You (BSNL) should take steps to prevent it," said the bench which also comprised Justice K S Radhakrishnan and Swatanter Kumar.

Giving a strict warning. the court said,"these things must stop" and also asked the PSU to take steps towards cancelling the interconnection agreement with such telecom firms.

The BSNL-Rcom row is before the sectoral tribunal TDSAT which had ordered the BSNL to show its Call Data Records (CDRs) to RCom to settle the issue.

Solicitor General Gopal Subramanium appearing for the BSNL submitted that despite being admitted by RCom of tampering of CLI, Telecom Disputes Settlement and Appellate Tribunal has directed it to show our records.

"Why should I be called upon to show my records," he said adding that Rcom has already paid Rs 20 crores in another CLI tampering issue.

On this senior advocate Vaidyanathan Aiyer appearing for Rcom said that the company has nothing to do with the call diversions.

The court has directed to list the matter on August 27.