The federal government Friday began implementing a law that would require insurers to provide benefits for mental health comparable to those for other medical services.

The Health and Human Services Department has published the final rules interpreting the sweeping federal legislation, which was passed in 2008, after a dozen years of  germinating on Capitol Hill.

New York has had its own state mental health parity law for insurers since 2006. Advocate Wendy Brennan says the local statute’s track record suggests one of the main challenges for the even broader federal law will be finding psychiatrists and other providers to treat people.

"Many mental health providers don’t take insurance, and it's particularly a problem for children’s mental health providers," said Brennan, head the New York City chapter of the National Alliance on Mental Illness. "And with greater access to care, at least on paper, that problem is only going to get more severe.

Dr. Jeffrey Lieberman, president of the American Psychiatric Association, agrees — and has called on his many cash-only colleagues to change their insurance-spurning ways.

"Providers need to change their way of doing business," said Lieberman, who practices psychiatry at Columbia University Medical Center. "The government’s done its part, bringing this legislation forward, as painful and difficult a process as its been, but we need to do our part, too."

He said he hoped that the mental health parity law would eventually lead to higher reimbursement rates for psychiatrists and other providers — but that they also will have to accept payments "below what the concierge or premium rates were."

"They need to accept that we're in a country where we're reforming healthcare, we're trying to provide care to the entire population and not just segments of the population, and still keep it an affordable amount of national expenditures," Lieberman said.

Psychiatrists who want to maintain their income, he said "will need  to see more patients" and clinics "will need to increase the efficiencies."

Brennan said she recognizes mental health treatment can be expensive, and insurance companies need to make money. But she and others suggest increasing the role primary care practices play in providing at least some mental health screening and treatment — diverting many people from costly specialists.

"We're going to have to compromise," she said.