The Department of Justice said this week that its antitrust enforcers will take action to ensure broadband competition if necessary, but that new rules are not necessary. Network neutrality advocates say that's not enough.

The U.S. Department of Justice said in a filing with the Federal Communications Commission that net neutrality regulations could "prevent, rather than promote, optimal investment and innovation in the Internet, with significant negative effects for the economy and consumers."

The department said the Internet has thrived in a free market and any new FCC regulations could limit consumer choice and investment in expansion of broadband capabilities.

"The term "net neutrality" encompasses a variety of proposals that seek to regulate how broadband Internet providers transmit and deliver Internet traffic over their networks," DoJ said in a statement. "The department stated that precluding broadband providers from charging content and application providers directly for faster or more reliable service could shift the entire burden of implementing costly network expansions and improvements onto consumers."

The department said "it may make economic sense for content providers who want a higher quality of service to pay for the Internet upgrades necessary to provide such service."

"Consumers and the economy are benefiting from the innovative and dynamic nature of the Internet," Thomas O. Barnett, Assistant Attorney General in charge of the department's Antitrust Division, said in a statement. "Regulators should be careful not to impose regulations that could limit consumer choice and investment in broadband facilities."

The department also noted that differentiating service levels and pricing is a common and often efficient way of allocating scarce resources and satisfying consumer demand. It added that post offices use different prices for different speeds of delivery.

"No one challenges the benefits to society of these differentiated products," the department stated in its filing. "Whether or not the same type of differentiated products and services will develop on the Internet should be determined by market forces, not regulatory intervention."

The department also echoed the words of net neutrality opponents who say there's no evidence of a threat to Internet access for ordinary Americans or small companies.

Net neutrality advocates say that without regulations, telecommunications and cable companies could create a tiered system that will give better service to those who pay more. The Open Internet Coalition wants preemptive safeguards to ensure that cable and telecommunications companies do not alter the current state of Internet accessibility.