PORTLAND — A union-backed group says signature-gathering efforts for nine of the 10 measures slated for the November ballot were riddled with fraud and forgery. All nine measures in question are sponsored by conservative activists.

But Don Hamilton, a spokesman for Democratic Secretary of State Bill Bradbury, was far more cautious Tuesday, saying most of the problems uncovered via a public records search by the left-leaning group Our Oregon date from before rigorous new rules on initiatives went into effect Jan 1.

“(Secretary Bradbury) does not see anything that is going to come under investigation for criminal fraud, because these were collected before the law changed,” Hamilton said.

The initiatives in question are sponsored by a clutch of conservatives, including anti-tax activist Russ Walker, former Oregon Republican Party chair Kevin Mannix and former Republican gubernatorial candidate Bill Sizemore. The proposals deal with a wide range of subjects, such as basing teacher salaries on classroom performance, curtailing bilingual education and imposing stricter sentences for property and drug crimes.

Scott Moore, a spokesman for Our Oregon, said the group’s examination turned up a “pretty clear pattern that there has been some forgery, no matter what the date is on the calendar. Oregonians need to know that the slate of ballot measures coming in November got there because of some fraudulent practices.”

Among the trends identified by Our Oregon:

n Petition sheets were copied using carbon paper, potentially allowing a signature given to just one initiative to be duplicated on a handful of others.

n Voters who sign petition sheets must also print their names and addresses; handwriting analysis suggests others might have sometimes handled that part of the task.

n Each signature gatherer must sign a sheet when they finish filling it with names. Moore said someone appeared to forge the name of a signature gatherer.

Sizemore denied any wrongdoing Tuesday, saying he was the victim of a vendetta.

“Our Oregon’s reason for existing is to stop the people of Oregon from voting on conservative measures — they will do anything,” he said.

He added that it’s news to him if signatures were copied.

“That kind of cheating is so unnecessary, it is hard to believe anyone did it,” Sizemore said.

“If there was someone caught doing that, they should put them in jail.”

Bradbury’s office has until Aug. 2 to verify the signatures on several initiatives that have yet to qualify for the ballot.