The California Secretary of State's office has warned the Sonoma-Marin Area Rail Transit District that it does not have legal authority to set rules for opponents attempting a voter repeal of the district's sales tax.

SMART's board of directors today will consider an ordinance that would require RepealSMART to submit a copy of its initiative for its review, which SMART contends is intended to make sure it is unbiased.

However, Lowell Finley, chief counsel to the secretary of state, in a letter Monday to SMART's attorney contends the proposal is counter to state law governing initiatives.

RepealSMART since mid-September has been circulating petitions to gather signatures for an initiative that would repeal the quarter-cent sales tax. It would be on either the spring or November 2012 ballot.

The group contends that SMART's funding is inadequate, that the proposed initial line from Santa Rosa to San Rafael is shorter than what was approved by voters in 2008 and that it would not generate enough ridership to reduce traffic and cut emissions.

What is unclear is how many signatures need to be obtained. The SMART opposition group contends that under Proposition 218 passed by voters in 1996, only 15,000 signatures are needed.

The Sonoma County Registrar of Voters, however, has advised opponents it would certify 15,000 signatures as sufficient, but said there is a risk that SMART would cite a state election code requiring 39,000 signatures, sending the issue to court.

There is a different election code that SMART is considering today, which sets the level of signatures that would require 30,000, according to the registrar of voters office.

However, SMART wants to require opponents to submit their initiative before collecting signatures, which the secretary of state's office contends is not required by state law.

SMART Chairwoman Valerie Brown said SMART's objective is to provide a process for the petition to be prepared in a fair and unbiased manner.

Brown said she spoke to the secretary of state's office on Tuesday and its opinion will be discussed today by the board.

"Right now we have two attorneys who don't agree," Brown said.

RepealSMART spokesman Clay Mitchell of Windsor said the group believes that 15,000 is the correct number and sides with the secretary of state in the ongoing debate.

SMART is meeting at 2:30 p.m. at San Rafael City Hall.