The head of the Federal Communications Commission will propose new rules to prevent Internet providers from selectively blocking or slowing Web traffic, a move that could set off a battle with phone and cable companies that don't want the government telling them how to run their networks.

In a speech Monday, FCC Chairman Julius Genachowski will lay out his rationale for new rules that would require all Internet providers to use "reasonable" network-management practices in dealing with Internet traffic, according to people familiar with the proposal. The rules would also be extended to include wireless arms of giants like AT&T Inc. and Verizon Communications Inc. as well as cable providers like Comcast Corp.

Currently, some wireless Internet providers prevent consumers from using some bandwidth-heavy Internet applications, like video file-sharing services, because of concerns they will slow cellular networks.

The agency will also ask for guidance on how to define "reasonable network management," since companies currently have little idea how the agency defines the term.

The FCC currently has four so-called net neutrality principles, which call on Internet providers to treat all legal Internet data equally. But it hasn't adopted formal rules.

Last year, Comcast Corp. challenged an FCC decision that it had violated the agency's net neutrality principles on the grounds that the FCC had never formally adopted such rules. That case is still pending in a federal appeals court. Mr. Genachowski's proposal is to turn the FCC's guidelines into rules, and erase the uncertainty over whether the rules apply to wireless carriers.

Wireless companies have argued that net neutrality rules don't apply to them and that they shouldn't, since data-heavy applications like Internet video can cripple their networks.

The FCC's proposed rules are expected to say that the agency plans to take into account the bandwidth limitations faced by wireless carriers, according to someone familiar with the plan.

President Barack Obama had pledged to the technology community that he would support net neutrality, and public interest groups have been waiting for the FCC to get the ball rolling on new rules.

"To me, net neutrality is a signature issue of the president in a tech policy area," said Ben Scott, policy director for Free Press, an public interest group which has pressed for strong net neutrality rules. "He's frequently endorsed the need for net neutrality. The record is by any measure full and expansive and the time for action is now."

Mr. Genachowski is expected to announce plans for the agency to open a formal rule-making process on the issue at its October meeting. The rules would have to be approved by a majority of the FCC's five-person board. Its three Democratic commissioners support net neutrality.

An FCC spokeswoman confirmed Genachowski will speak on Monday.

Write to Amy Schatz at Amy [dot] Schatz [at] wsj [dot] com