The governor of the US state of Illinois has been thrown out of his job and barred from ever holding public office in the state again, following his conviction in a senate impeachment trial.

Illinois state senators voted unanimously 59-0 that Rod Blagojevich had abused his powers, ignoring a last-minute plea that he had done "absolutely nothing wrong".

The governor had been accused of trying to auction off the US senate seat vacated by Barack Obama, the US president.

In a damning indictment shortly before Thursday's vote, one senator labelled Blagojevich a "devious, cynical, crass and corrupt politician, and someone from whom the people of this state must be protected".

"He should be removed from office, and he should be prohibited from ever holding office in this state again," Senator Dale Righter said.

Blagojevich becomes the first US governor in more than two decades to be removed by impeachment.

Patrick Quinn, the lieutenant governor of Illinois, was sworn in almost immediately as Blagojevich's replacement.

'Fixed deal'

Speaking to reporters and neighbours outside his Chicago home on Thursday, Blagojevich said he was saddened but not surprised by the decision.

Earlier on Thursday, Blagojevich, who boycotted the first three days of the trial and refused to answer questions from state legislators, made an impassioned plea to save his job.

"I have done absolutely nothing wrong," he said.

"How can you throw a governor out of office who is clamouring and begging and pleading with you to give him a chance to bring witnesses in to prove his innocence?

"I followed every law ... and when the whole truth is heard, and the whole story is told, that ultimately is what will be shown."

Members of the Illinois senate though were not swayed by his plea saying the limited evidence they were allowed to examine was more than sufficient.

"The governor's word is not worth the paper it's written on," Senator John Jones said.

More trials

Among the allegations against Blagojevich were several corruption accusations contained in a 76-page FBI affidavit.

The governor has not yet been indicted on the fraud and extortion charges, and his criminal trial has yet to start, but Illinois legislators said the evidence against him was staggering.

Five of the past nine Illinois governors have been indicted or arrested for fraud or bribery and Blagojevich's predecessor, Republican George Ryan, is serving a six-and-a-half year sentence for fraud and racketeering.

The last US governor to be impeached was Evan Mecham, Republican governor for Arizona, in 1988.