WASHINGTON  The Federal Communications Commission will propose rules on Thursday requiring mobile phone companies to alert customers by voice or text message when they are have reached monthly usage limits and are about to incur extra charges, the commission’s chairman said Tuesday.

Julius Genachowski, the F.C.C. chairman, will propose what he calls the commission’s consumer empowerment agenda, aimed at ensuring that users of new technologies do not have to worry about hidden costs, confusing billing practices and what the commission calls “bill shock.”

In an interview on Tuesday, Mr. Genachowski said that the five-member commission would consider proposed rules that also would require cellphone and mobile Internet companies to notify customers when they were about to incur roaming charges or other higher-than-normal rates that were not covered by their monthly plans.

The proposals, which have been strongly opposed by mobile phone companies and their trade groups, are expected to be approved by a majority of the commission at its monthly meeting Thursday. The chairman’s office rarely brings matters to a commission vote without the support of a majority of the board.