South Korea's disgraced ex-president Park Geun-hye is serving 24 years in jail and has been fined millions of dollars for bribery and abuse of power in a massive corruption case

Three former South Korean spy chiefs were jailed Friday for illegally funnelling millions of dollars from the country's intelligence agency to disgraced ex-president Park Geun-hye.

The trio were convicted of diverting a total of 3.5 billion won ($3.2 million) to Park while they each served as head of the National Intelligence Service (NIS) under the then-president between 2013 and 2016.

"Special activities funds of the NIS should be spent on collecting intelligence", the Seoul Central District Court said in a statement.

The court found them guilty of diverting state funds but dismissed bribery charges, citing the lack of evidence that they received any favours from Park in return for the funds.

Of the three ex-NIS heads, Lee Byung-kee and Lee Byung-ho were both sentenced to three-and-a-half years in prison.

The third, Nam Jae-Joon, was jailed for three years. Nam is already in prison after being given 42 months in May for obstructing prosecutors investigating meddling by the NIS in the 2012 presidential election.

Prosecutors on Thursday also demanded an extra 12 years' jail time for Park for accepting the NIS funds as bribes.

She is currently serving 24 years in jail and has been fined millions of dollars for bribery and abuse of power in a massive corruption case which led to her downfall.