The complaint, which also names the county committee and was filed Friday on behalf of John Daly in Superior Court, claims the committee did not take nominations from the floor.
Daly, a Democrat, is running alongside Fire Chief John Hoffman and Scott Dziegrowski. Daly's attorney, John Trimble, said the three were seeking a "level playing field," asking that both groups be placed on the ballot outside the regular party line.
Trimble pointed to Monroe Township, where two groups of Democrats filed petitions, both without the county slogan.
"There's a split in how things should run - whether they should be open and transparent, or selections should be made by a few without the full committee's involvement," Trimble said of the Washington Township committee Monday.
The suit asks for the removal of Chairman Frank Cianci and for the committee-approved candidates to lose their endorsements.
Cianci on Monday called the lawsuit frivolous.
"We did everything correct," he said. "We've been doing endorsements like this for years."
Cianci declined to comment further, referring questions to attorney John Eastlack, who did not return a call for comment.
The Democratic committee fracture trails an ongoing split on the Republican side.
The Washington Township Republican Executive Committee in January announced that it would not support Council President Giancarlo D'Orazio for reelection this year.
With Republican Councilmen Chris Del Borrello and Daniel Morley not seeking a second term, the committee is backing Christine Bailey, Joseph Micucci, and Nicholas Fazzio. D'Orazio filed a petition to run alongside Robert Maloney, under an "Independent Republican" slogan.
D'Orazio was elected council president in January with the votes of the two Democrats, who are not up for reelection this year.
"He hasn't conferred with us" on votes or decisions, said Jack Yerkes, Republican committee chairman. "Everything has been done behind the scenes in an attempt to empower himself."
D'Orazio countered that the committee took issue with his not voting along party lines: "If this puts me in hot water with my local party, so be it."
After years of Democratic majority, the three current Republicans gained the upper hand of the five-person council after a victorious 2010 election. But that advantage has been tainted by the conflict between D'Orazio and the committee. His fellow Republicans took issue with several of the council president's decisions, including the appointment of Jill McCrea, a former township Democratic committee chairwoman, to the clerk position.
The Gloucester County GOP on Monday also named its three candidates who will challenge incumbents for positions on the Democratic-controlled freeholder board this November.
Incumbents Heather Simmons, Adam Taliaferro, and Lyman Barnes will face Joseph M. Bennis, Jeanine Butterworth-Green, and Christopher Hervochon.