WA bookkeeper facing 74 corruption charges

A bookkeeper who denies helping a senior bureaucrat and another man carry out Western Australia's biggest public sector theft has been slapped with an additional 65 charges.

Paola Colangelo, 45, has already pleaded not guilty to nine corruption charges.

Police allege Colangelo, who is not a state government employee, acted in concert with former Department of Communities executive Paul Whyte, 56, and 43-year-old physiotherapist Jacob Anthonisz.

The men are each facing more than 500 charges after allegedly raising false invoices for three shelf companies dating back to 2008.

They allegedly spent the money on racehorses, paying a horse stud service in New Zealand, and personal expenses and bills.

Whyte has signalled he will likely plead guilty over his role in the alleged $22 million rort.

Colangelo is due to face Perth Magistrates Court on May 1.