A federal judge on Wednesday rejected a conservative challenge to health insurance subsidies available to people in the 34 U.S. states that declined to establish their own online marketplaces under President Barack Obama's healthcare law.

The suit, brought by individuals and businesses from Texas, Kansas, Missouri, Tennessee, West Virginia and Virginia, asserted that the wording of the 2010 law allowed subsidies to help people obtain insurance only in exchanges established by states, not those set up by the federal government.

In his ruling, U.S. District Judge Paul Friedman wrote that Congress clearly intended to make the subsidies available nationwide under the new law.

"There is evidence throughout the statute of Congress's desire to ensure broad access to affordable health coverage," the judge wrote.

Michael Carvin, a lawyer for those who brought the suit, filed a notice that he would appeal the ruling within an hour after it was posted online.

"This decision guts the choice made by a majority of the states to stay out of the exchange program," Sam Kazman, another lawyer for the plaintiffs, said in a statement.

The law, dubbed Obamacare, aims to provide health coverage to millions of uninsured or under-insured Americans by offering private insurance at federally subsidized rates through new online health insurance marketplaces in all 50 states and in Washington, D.C.

Only 14 states opted to create and operate their own exchanges, leaving the Obama administration to operate a federal marketplace for the remaining 36 states that can be accessed through HealthCare.gov.

The exchanges were launched last October.

A spokeswoman for the Justice Department, which is defending the law, said officials were pleased with the decision.

The subsidies, in the form of tax credits, are a key part of the healthcare overhaul. They are available to people with annual incomes of up to 400 percent of the federal poverty level, or $94,200 for a family of four.