A Los Angeles city councilman has called for a new citywide tax on billboards, digital signs and supergraphic advertisements, saying the proceeds could go a long way toward easing the city's long-term budget woes.

Councilman Herb Wesson sent a letter Thursday to Councilman Bernard C. Parks, head of the council's budget and finance committee, saying that an advertising excise tax could generate as much as $50 million annually if it were passed in November by the city's voters. The city faces a budget shortfall of $485 million.

The proposal was one of several offered by Wesson in a letter arguing that the council should do everything it can to minimize the number of layoffs and furloughs planned for the fiscal year that starts July 1. The council is weighing a plan from Mayor Antonio Villaraigosa that would eliminate as many as 761 employees and impose up to 26 furlough days for certain workers.

As part of his push to scale back those cuts, Wesson called for the council to boost ambulance fees, offer early retirement to 100 more city workers and secure an additional $20 million from the Department of Water and Power.

"Throughout the budget, there is a need to be more creative in identifying additional revenue sources that will shore up the city's finances, as well as gain voter approval," wrote Wesson, who represents portions of Koreatown and South Los Angeles.

Wesson also said the city should wring new concessions from unionized city workers and impose financial penalties on banks that do not maintain foreclosed properties.

The notion of a sign tax drew support from Stuart Waldman, president of the Valley and Industrial Commerce Assn., who said the idea was long overdue. Still, other parts of the proposal were greeted skeptically by Parks.

Parks' chief of staff, Bernard Parks Jr., said the councilman concluded that Wesson's proposal bore a strong resemblance to a budget plan offered in April by the Coalition of L.A. City Unions, which represents 22,000 city employees. Parts of that plan have been "discredited" by budget analysts, he said.

Wesson's proposal could shift the budget debate on the 15-member council, which is already divided into two camps, with several council members floating in between.

Council members Parks, Greig Smith and Jan Perry have been the most vocal about their support for deep cuts to the workforce. Council members Richard Alarcon, Paul Koretz and Janice Hahn have argued forcefully against them.

Two of the council's more hawkish members, Perry and Dennis Zine, were added to the budget committee in recent weeks by council President Eric Garcetti. That move was viewed by some labor activists as an effort to realign the committee so that it has more members favorable to cuts.

City Administrative Officer Miguel Santana would not discuss Wesson's letter. But he argued that a reduction in the workforce is needed to address the city's long-term budget woes.

"It's going to come down to structural change, versus surviving one more year," he said.