The Department of Telecom, he said, is likely to send "show cause notices as well as an advisory to stop (3G) services.
"There are show cause notices as well as advisory to stop the services. I expect that they would go out today," he told reporters here.
Asked if the notices will be issued today, he said, "Possibly I can't say exact time but decision has been taken and notices will go out."
DoT has held that it is illegal to offer third-generation or 3G data services beyond a company's licensed zone or circle. Telecom companies had challenged the order before the Telecom Disputes Settlement and Appellate Tribunal (TDSAT), which in July gave a split verdict.
Chandrashekar refused to name any of the companies which are being asked to immediately stop 3G services, but said notices will go out to people who have committed a breach.
Asked if the operators will get 60 days time, he said, "Stoppage will be immediate (and) time given (to them) is for responding to the reasons for breach."
In December, the Government had issued notices to leading telecom firms asking them to stop their 3G roaming agreements as the pacts were illegal.
The operators had entered into agreement with one another to offer 3G mobile services in circles in which they could not succeed in getting spectrum in the auctions held last year.
However, the operators had challenged before TDSAT the DoT directions, issued on December 23, to scrap the pacts within 24 hours.
TDSAT had given a split verdict in the 3G intra-circle roaming case with its chairman allowing operators' plea against the government order to stop the service, while its member dismissed it.
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