Marriage Equality USA policy director Pamela Brown said she believes the reason for increased interest in the march is a pending federal court challenge to Proposition 8, California's ban on same-sex marriage.
"I hope we've finally reached a tipping point where we as a state and a nation see there's no justifiable reason for denying gay and lesbian couples the right to marry," Brown said this morning.
"We think there will be great interest in the march," she said.
In the Proposition 8 case, U.S. District Judge Vaughn Walker of San Francisco last month struck down the marriage ban, ruling that it violates the federal constitutional rights of equal protection and due process.
The decision is on hold while sponsors of Proposition 8 appeal to the 9th U.S. Circuit Court of Appeals in San Francisco. The appeals court is due to hold a hearing on the case during the week of Dec. 6.
Marriage Equality submitted a friend-of-the court brief supporting two couples who filed the federal lawsuit challenging Proposition 8.
Sunday's Bridge Walk, which begins at Crissy Field in San Francisco at 9 a.m., is the seventh annual event.
A similar walk will take place on New York City's Brooklyn Bridge.
Brown said about 125 people participated in the Golden Gate Bridge march last year, but organizers this year are expecting numerous couples from around the state who want to get married.
"We need to be visible and we need our voices heard," Brown said.