The Service Employees International Union and an activist women's group, Working Women, have joined in an attempt to capture a share of the nation's 20 million mostly nonunion and mostly female clerical workers.

The marriage of convenience between the male-led union and Working Women occured Monday in a civil ceremony marked by what both parties called a "multiyear contract for an organizing drive funded by SEIU and jointly directed by the two groups."

The two parties said in their public announcement yesterday that each would keep its respective identity, but would work through an newly created collective bargaining/organizing unit, District 925 (as in "nine to five"), to go after the clericals.

The organizing campaign will be "targeted at one of the largest and fastest-growing segments of the work force," said SEIU President John Sweeney whose union -- though dominated by male leaders -- has 650,000 members, more than 50 percent of whom are women.

"Lacking trade union representation, office workers are among the most underpaid and abused of the work force," Sweeney said. "The Service Employees union has built its reputation representing workers at the lowest end of the pay scale, and we look forward to this new challenge with a great deal of determination and even relish."

However, other unions, facing declines in their original membership bases, have similar designs on clerical workers. For example, the United Auto Workers won the right on Jan. 22 to represent 3,300 Detroit-area Blue Cross-Blue Shield office workers, about 80 percent of them women. Now the UAW is attempting to organize clerical workers at Cornell University in Ithaca, N.Y.

The Cleveland-based women's group has aimed most of its actions at banking and savings and loans institutions, considered to be among the hardest of the hard-to-organize clerical sectors. But Working Women, without collective bargaining powers, has walked away from the skirmishes with significant salary increases at places such as Maryland National Bank in Baltimore and multi-million-dollar discrimination suit settlements at places such as Chase Manhattan Bank in New York.