JUNEAU (AP) -- Lt. Gov. Loren Leman stopped an initiative drive seeking to decriminalize marijuana, ruling Tuesday that hundreds of signatures collected were not valid.

Leman, a former state senator who sponsored a bill in 1999 to turn back the state's medical marijuana laws, said in a statement that the pro-marijuana group will have to begin from scratch to get its measure before voters in 2004.

The proposed initiative would have asked voters in the August 2004 primary ballot to decriminalize and regulate marijuana.

Backers submitted 484 booklets containing signatures of Alaskans who supported putting the measure on the ballot. But officials with the state Division of Elections found several discrepancies in the petitions, Leman said in a press statement.

In several instances the identity of those who signed the petitions could not be verified or were not registered voters, a spokeswoman for the Division of Elections said.

Election workers also did not count 194 booklets containing signatures because of poor record keeping, the division said.

Alaska law requires a petition drive collect signatures equal to 10 percent of the voters in the previous statewide election to get an initiative on the ballot.

Backers of the marijuana initiative needed 28,782 signatures to get the measure on the 2004 ballot. The state Division of Elections verified 21,737 signatures of registered voters, said spokeswoman Virginia Breeze.

The lieutenant governor's office said initiative sponsors will have to start the petition process again to get it on the ballot.

Georgia Mario of Chugiak plus Anchorage residents Tim Hinterberger and Randall Patterson were listed as primary sponsors of the initiative. They could not be reached for comment Tuesday.

The Alaska H.E.M.P office in Juneau was closed Tuesday afternoon.