Maryland's delegation to the Democratic National Convention is refusing to attend a city-hosted reception here Sunday night, after a Boston police union declared it will go forward with plans to picket 29 state welcome parties, despite an arbitrator's ruling that settled a protracted contract dispute with the city.

Officials for the Boston Police Patrolmen's Association, which will receive a 14.5 percent raise over the next four years, said they will carry out their protest on behalf of other municipal unions that lack contracts and to show their displeasure with the way their binding agreement came about.

"Certainly we are very, very disappointed," said Maryland Democratic Party Chairman Isiah Leggett. "But Maryland has a very large contingent of labor delegates . . . and we are quite sensitive of the collective bargaining process, and it is something we take very, very seriously." Instead of attending the city-sponsored reception at the Boston Children's Museum, Leggett said Dominion Power will sponsor a party for the Maryland delegates at Boston's World Trade Center.

Montgomery County Executive Douglas M. Duncan (D) sent a letter to Maryland delegates Thursday urging them to boycott all convention events where pickets are established.

The fractious dispute forces Democrats from across the country to make a difficult choice between supporting a smooth-functioning convention and standing up for organized labor, a traditionally strong party ally. Last week, union officials wrote to each state delegation asking them to skip the welcome parties, while the Boston host committee and Mayor Thomas M. Menino (D), who has been under siege by union demonstrators here for months, wrote to ask delegates to attend.

District Democratic Party Chairman A. Scott Bolden said he hopes the labor dispute is resolved by Sunday so the pickets do not materialize. If they do, Bolden said District Democrats will honor them and not attend a reception also at the Boston Children's Museum. "We have no intention of crossing any informational picket lines," he said.

Lawrence H. Framme III, the head of the Virginia delegation, said individual delegates from that state will be free to decide whether they want to cross a picket line. The co-chairman of the delegation, Fairfax County Board of Supervisors Chairman Gerald E. Connolly said he will not attend any event at which union members are picketing. "It is awkward. We are trying to have a national convention in the midst of a labor dispute," he said. "I just make a practice of respecting the right of organized labor to strike. I will respect their picket line."

Convention organizers on Wednesday canceled welcome parties for two states, Michigan and Ohio, and the leaders of several others, including Art Torres, who heads the California delegation, the nation's largest, have asked members not to cross picket lines.

For months, City Hall negotiators stuck to an offer of an 11.9 percent raise while the police union demanded 17 percent. Hoping to resolve the dispute before the convention begins Monday, a state mediation board this week sent the dispute to expedited arbitration and gave a Thursday afternoon deadline. The union's attempt to stop the process with a court injunction was denied on Tuesday.

The Boston City Council must grant its approval to the contract terms set by arbitrator Lawrence T. Holden Jr., and Menino said he had asked the council to do so.

Jim Barry, a spokesman for the 1,400-member BPPA, called the agreement "an engineered railroading" and "a disgrace." The union was denied by the arbitrator in its bid to ease city residency requirements for patrolmen and to secure longevity pay for experienced officers. "Not knocking the wages, but there are a myriad other issues not addressed by this contract," Barry said, adding that "unfortunately, it's done."

But the mayor, who along with Massachusetts Gov. Mitt Romney (R) had argued that demonstrations by emergency personnel would compromise the safety of the convention, said the pretext for any protests was gone. "What the arbitrator basically did was split the difference," said Menino, who added that the patrolmen's raise would cost the city $8.6 million. "There's no other reason for them to picket right now."

The city also earned a split decision Thursday in a pair of legal cases brought by activists intending to protest the convention. U.S. District Judge Douglas P. Woodlock overturned the Boston Police Department's denial of a permit for groups planning a Sunday parade down a street in front of the FleetCenter, where the convention will be held.

Woodlock also ruled that the city was not required to modify a 28,000-square-foot demonstration zone near the FleetCenter that activists had argued was unsafe and too heavily barricaded to allow them to interact with delegates.

"We are pleased that we won the right to march on the convention," said Peter Cook, an organizer for Act Now to Stop War and End Racism, a party to the parade suit. "We will encourage people not to go to the demonstration zone, which we feel is an abomination."

Craig reported from Washington. Staff writer Michael D. Shear in Richmond contributed to this report.

Boston Mayor Thomas M. Menino talks yesterday about the settlement to a two-year contract dispute between the city and its police union.