Federal and state regulators and lawmakers are stepping up pressure on the insurance industry for offering plans under ObamaCare that limit access to doctors and hospitals -- a strategy insurers say is necessary to keep coverage prices low in the health law's marketplaces.

The Wall Street Journal reports that some state legislatures are weighing bills that could force insurers to add more hospitals and doctors to plans, while federal regulators have proposed a tougher review process for plans to be sold next year through HealthCare.gov.

The access problem is a byproduct of the effort to drive down costs of subsidized coverage, prompting insurance companies to offer limited choices of doctors and hospitals.

Under a federal proposal announced this week, insurance companies selling plans in the federally-run marketplace would be required to submit to the government a full list of providers in a network before the plans are approved for the exchanges, The Wall Street Journal reported.

A spokesman for the Centers for Medicare and Medicaid Services told the newspaper it is "working to strengthen the network adequacy requirements that took effect for this year."

In Washington state, Seattle Children's Hospital has sued over the state insurance department's decision to approve networks that didn't include the facility. The hospital is excluded from five of seven plans on Washington’s state insurance exchange, according to Bloomberg News.

The hospital says is struggling to get paid for care given to about 125 children it has treated since Jan. 1, when ObamaCare coverage took effect. The facility will be required to pick up costs beyond the standard deductible if insurers refuse to cover their services.

"We made the decision to see all the children," Sandy Melzer, the facility's strategy officer, told Bloomberg News. "Maybe we’ll be paid, maybe we won’t. It’s completely done on faith."

The family of 5-month-old Gabriella Blankers visited Seattle Children’s last month for a CT scan that found a rare birth defect. They said they were initially rejected by their insurer because the hospital wasn't in their network, though the insurer later made a temporary exception, according to the report.

"There’s nowhere else I could go," to get the care Gabriella needed, Rebekah Blankers, the girl’s mother, told Bloomberg News. "Unless I went out of state, out of network, or out of pocket."

Lawmakers in a Washington state Senate committee heard a proposal this week that would reportedly allow health insurance companies to keep offering insurance plans that don't meet the new federal and state requirements. But they would only be offered to people who were enrolled in such plans as of Oct. 1, 2013.

Senate Bill 6464 also would let insurers from other states sell plans to Washingtonians without requiring the carriers to meet Washington state insurance regulations.

When President Obama announced he would leave it up to the states to decide whether to continue to offer some old plans for a while, Washington's Insurance Commissioner Mike Kreidler said he would not allow it.

Meanwhile, in Mississippi, proposed legislation would bar insurers from cutting off most doctors and hospitals that agree to prices set by insurers. The bill also would prohibit insurers from charging higher copayments at certain doctors' offices or hospitals, according to The Wall Street Journal.

Click here for more from The Wall Street Journal.

Click here for more from Bloomberg News.

The Associated Press contributed to this report.