A former Colorado county election official has been sentenced to nine years in prison for tampering with voting machines after the 2020 presidential election.

Tina Peters, a Republican, was convicted last August on most counts against her in the election interference case.

Peters helped breach Mesa County's election computer systems and allowed an unauthorised individual to access voting equipment and election records.

She carried out the breach amid unsubstantiated claims that mass voter fraud had caused former President Donald Trump to lose the White House in the last presidential election.

Peters became a well-known figure among fellow election deniers who believed the 2020 presidential election was rigged and was stolen from Trump.

She pleaded not guilty to all counts in 2022. A jury convicted her on seven of the 10 counts in which she was charged.

Those include three counts of attempting to influence a public servant, one count of conspiracy to commit criminal impersonation, first-degree official misconduct, violation of duty and failing to comply with the secretary of state.

A judge sentenced Peters to eight and a half years in the Colorado Department of Corrections and additional time in the Mesa County Detention Center.

"Tina Peters has been sentenced to nine years of incarceration for her dangerous attempts to break into her own election equipment to prove Trump's 'Big Lie'," Colorado Secretary of State Jena Griswold said in a statement. "We will not allow anyone to threaten our elections."

The case marks the first time a local election official was prosecuted over a security beach in the 2020 election.

Prosecutors said Peters helped breach the county's election computer systems and allowed an unauthorized individual to access voting equipment and election records. The person posted secure election equipment images online.

Peters became "fixated" on voting problems after the presidential election, prosecutors said.

Investigators also issued a search warrant for MyPillow founder Mike Lindell, a proponent of election fraud claims, in connection to Peters' case, BBC's American partner CBS News reported.