San Francisco City Hall could be filled once again with naked people on Tuesday when the city's Board of Supervisors is expected to give its final approval to a citywide ban on nudity.

Several nudists stripped down on Nov. 20 when the board gave initial 6-5 approval to the ordinance, introduced by Supervisor Scott Wiener, and said they plan to do the same Tuesday.

The legislation would amend the city's police code to prohibit nudity on city streets, plazas, sidewalks and other public spaces, with exceptions for permitted parades, fairs and festivals.

Activist Gypsy Taub, who has organized several nudist rallies, wrote on her website to encourage opponents of the ordinance to speak out at Tuesday's meeting and to take action if the legislation is passed.

"If they reject the ban - we celebrate our victory," Taub wrote. "If they approve the ban we all get naked! Either way it's going to be fun!"

At the Nov. 20 meeting, sheriff's deputies were ready with blankets that they draped over people who stripped off their clothes. The protesters were then escorted out of the meeting.

If the approval is finalized, the ordinance would take effect on Feb. 1, 2013, although opponents have also filed a lawsuit seeking to block the legislation.

The ordinance would set fines that start at $100 and rise for each additional offense within a year. Violators would not be required to register as sex offenders.