Social service providers complained Wednesday after dissident Democrats halted legislative activity in the Massachusetts House for a third consecutive day.

Four members used a parliamentary tactic to prevent any action, including a vote on $41 million to address homelessness and a $100,000 death benefit for the family of a Quincy police officer struck and killed by a car while on duty earlier this year.

"We're really allowing this political process to play out on the backs of children," Diane Sullivan, policy director for Homes for Families, said as she stood outside an empty House chamber.

Her colleague at the nonprofit agency, Libby Hayes, said they were getting nervous because shelter contracts will expire Dec. 31.

The four dissidents _ Lida Harkins of Needham, William Greene of Billerica, Thomas Stanley of Waltham and Matthew Patrick of Falmouth _ say they are upset at being rebuffed as they seek an explanation for a $378,000 bill the House received for legal services related to a federal investigation of former Speaker Salvatore DiMasi.

They say the bill far exceeds a $40,000 tab incurred by the Senate after two of its members faced legal problems during the past year.

The new speaker, Robert DeLeo, says the bill is for document analysis services provided by a Boston law firm to comply with federal subpoenas. DeLeo supporters have argued the dissident House members are upset with being demoted under DeLeo's regime, and because the speaker laid off some of their staff members this month.

Although DeLeo agreed Tuesday to have an outside attorney review the bill, the four legislators shut down the chamber again Wednesday, as a single member can do when the Legislature is meeting informally.

The shutdown came just hours before many of the 144 Democrats in the 160-member chamber gathered for a party caucus, ostensibly to discuss an education reform bill. Yet DeLeo began the closed-door session with a vigorous defense of the legal spending, as well as his decision to seek an attorney's review, according to members who left the session.

Harkins and the other dissidents have called for an independent review by an accountant, but House attorneys argued that would relinquish attorney-client privilege for the chamber.

DiMasi resigned in January and was indicted in June on charges he received $57,000 for helping engineer a state contract for a software company, and also concealed his interest in a property management firm running the state Transportation Building.