President Obama's centerpiece climate change regulations are expected to be published as soon as this week in the Federal Register, signaling the start of lawsuits and a Republican effort to scuttle the rules.

The Environmental Protection Agency and the Justice Department told a federal court that the power plant rules, called the Clean Power Plan, would take months to be published in the Federal Register after they were finalized Aug. 3.

Clean Power Plan critics say the Obama administration is purposefully delaying the publication of the rules to slow legal challenges and stall threats from the Republican leadership that plans to initiate a legislative campaign to squash the plan.

The rules put states on the hook to cut their greenhouse gas emissions one-third by 2030. The landmark rules are the linchpin in the climate change agenda of Obama, who wants to secure an international global warming deal with global leaders in Paris in December. Many scientists blame increased greenhouse gas emissions from fossil fuels for the rise in global warming.

Sixteen states are planning to file a lawsuit as soon as the rule is published, with business groups and possibly more states ready to join. The lawsuit will challenge the constitutionality of the rule, saying that the EPA is exceeding its authority.

Based on the timeline the EPA provided to the D.C. Circuit Court of Appeals in August, the rule is slated to be published by the end of October, say lawyers tracking the rule.

In September, EPA Administrator Gina McCarthy told the Senate Environment and Public Works Committee that the Clean Power Plan was sent to the Federal Register on Sept. 4 awaiting publication in October.

In a letter obtained by the Washington Examiner earlier this month, Oliver Potts, the director of the Federal Register, told Republican Sen. Shelley Moore Capito of West Virginia that he was unable to provide information on the timing of the rule.

Capito, who is chairwoman of subcommittees in both the environment and appropriations committees, asked the Office of the Federal Register to confirm when the EPA sent the rule, whether or not the agency has sent all information required for publication of the climate rules, if the EPA specified a specific date it wished to have the rule published and when the rule would be published.

Potts said none of the information could be disclosed as per federal rules.

Capito argued that delaying publication of the power plant regulations would slow state challenges to the Clean Power Plan being led by her state. She said that is troublesome because states are required to begin drafting compliance plans and submit them to the EPA by Sept. 16, 2016.

"Further delays in publication will imperil the ability of Congress and the federal judiciary to meaningfully review this rule before states must begin the process of complying with its costly mandates," Capito wrote in a letter send to Potts Oct. 5.

In addition to 16 states ready to sue the agency, Capito also disclosed plans for the GOP to attack the rule.

"A prepublication version of the Clean Power Plan rule has been released and in response, I drafted a Congressional Review Act Resolution of Disapproval that would repeal the existing plant rule in its entirety," she wrote. "Similar legislation is developing in the House of Representatives."

Until the rule is published in the Federal Register, the litigation and congressional resolution to repeal the Clean Power Plan cannot proceed.