The Internal Revenue Service has slapped the Housing Authority of Baltimore City with a federal tax lien, alleging the agency owes more than $626,000 in payroll taxes.

Officials at the housing authority, however, say the IRS is mistaken and that no back taxes are owed. Housing officials have been trying without success to reach the IRS for an explanation for a week since learning about the lien from a reporter. The document was filed in Baltimore Circuit Court on Oct. 9.

Rainbow Lin, chief financial officer for HABC, has reviewed the authority's financial records and believes they are in order, said Melvin Edwards, housing spokesman. Sam Serio, a spokesman for the IRS, declined to comment, saying tax matters are confidential by law.