The King County (search) Canvassing Board decided Wednesday to begin the process of verifying 573 newly discovered absentee ballots that could change the outcome of Washington's extremely close race for governor.

The board has yet to decide whether any of those ballots will be counted, but its move was a victory for Democratic candidate Christine Gregoire (search), who trailed Republican Dino Rossi (search) by 42 votes after a machine recount.

King County, which includes Seattle, is a Democratic stronghold that is expected to be the last of the state's 39 counties to complete a hand recount of all ballots. The recount is expected to be finished Dec. 22.

King County election officials said they discovered Sunday that 573 absentee ballots had not been counted because the voters' signatures had not been scanned into the county's computer system. Election workers should have checked the paper files, but instead the ballots were mistakenly rejected.

County Elections Director Dean Logan said he believes most of the 573 ballots belong to valid, registered voters.

Still to be decided was the fate of 22 other newly discovered ballots. They were found in several polling places in the side bins of plastic bases in which polling machines sit, said Bill Huennekens, county election superintendent.

State Republican Party Chairman Chris Vance urged the canvassing board not to count the newly discovered ballots.

"None of these ballots should be counted," Vance said. "At the very least, the King County canvassing board needs to slow down and figure out what's going on with these ballots."

The canvassing board voted 2-1 to move forward with recanvassing the 573 ballots, a process that will take several days. After election workers determine whether the ballot signatures are those of registered voters, the board will decide whether the votes should be counted.

As of Wednesday, with all but the four most populous counties reporting results of their hand recounts, Rossi had gained 81 votes for a margin of 123.