Red-faced state officials admitted last night they are trying to find as many as 19,000 missing welfare recipients — after the controversial taxpayer-funded voter registration pitches the state mailed to their addresses last summer were sent back marked “Return to sender, address unknown.”

The Department of Transitional Assistance contacted 477,000 welfare recipients who were on their books from June 1, 2011, to May 31, 2012, after settling a voter-rights lawsuit brought by Democratic-leaning activist groups that demanded an aggressive voter information effort by the state. That $274,000 push by DTA resulted in 31,000 new voter registrations — but revealed an alarming number of welfare recipients whose residency in Massachusetts can’t be confirmed. “
DTA is in the process of contacting those clients for which a forwarding address was prov­ided to verify their addresses, as a change of address might impact their eligibility,” a statement from the agency said.

DTA critics expressed astonishment at the agency’s faulty address records — which were only uncovered by accident — saying it’s further evidence that the electronic benefits system sorely needs reform.