HARRISBURG — Gov. Tom Corbett on Wednesday began seeking federal approval for his plan to bring billions of federal Medicaid expansion dollars to Pennsylvania to cover a half-million working poor residents through private health plans, although advocates for the poor and uninsured called it bureaucratic and punitive.

The Corbett administration submitted the plan to the U.S. Centers for Medicare and Medicaid Services, which has given at least partial approval to proposals by other states, including Arkansas and Iowa, which sought some similar modifications to the Medicaid expansion envisioned by the 2010 federal health care law.

Corbett’s public welfare secretary, Beverly Mackereth, said the administration is backing off certain elements that have been criticized as barriers to coverage, although not enough to mollify every critic of a draft plan with a long list of conditions the administration issued in December.

In any case, any new coverage is expected to wait until January 2015, when Mackereth has said the administration will have the technology and staff to handle the new program.

Meanwhile, the Republican governor is running for a second four-year term this year and may have to sustain criticism until then that he did not move quickly enough to draw down the federal Medicaid expansion dollars when they became available Jan. 1.

Corbett, a critic of Medicaid who calls the five-decade-old program inefficient and bloated, refuses to expand Medicaid coverage. Instead, he wants to use the Medicaid expansion dollars to purchase private insurance policies for about 500,000 newly eligible adults, an idea pioneered by Arkansas.