Melinda Jane Trembath, 45, creator of food company Melinda's Gluten Free Goodies, apparently believed she was joining the lifelong family friend in researching cancer.

Instead, the mother of three became a vital cog in a $3.6 million bid to defraud the Australian Taxation Office through a fake research and development tax offset claim.

The family friend, who has been charged but is yet to face court, was described as the main instigator of the elaborate scam. She had lost her mother to cancer after she had previously taken part in clinical cancer research trials.

The woman allegedly created two biotechnology companies, appointing Trembath to be a director.

In 2017, the companies lodged a tax offset claim of $3.6 million. When the ATO queried the claim, Trembath used her extensive business experience to forge a paper trail to justify the dodgy return.

The court was told Trembath created fake invoices and bank statements and was charged with four counts, including forging documents and attempting to influence a Commonwealth public official.

Trembath pleaded guilty to all four charges in the Brisbane District Court on Monday.

"Her role was by no means minor," the prosecution told the court.

"She agreed to be the director of two companies. She took active steps using her business skills to forge documents to perpetuate this fraud."

While the family friend allegedly devised the scheme, Trembath actively took steps to disguise the attempted fraud, the court was told.

"It was an act to defraud the Commonwealth and ultimately the taxpayer of over 3.6 million."

Defence barrister Daniel Caruana said Trembath knew what she was doing wrong but did not deserve to go to jail.

"It all boils down to the fact this has been a huge betrayal," Mr Caruana said.

"There was a document found ... and it's quite bizarre and shocking that instead of going toward important medical research, (the co-accused) was looking to buy a mansion for herself.

"That was a shock to my client - she felt terribly betrayed by someone she thought was a friend.

"It was a staggeringly sophisticated scheme."

In sentencing, Judge Orazio Rinaudo said the scheme relied on Trembath's expertise in business and went along with the fraud out of a "false sense of loyalty".

"The documents which you (Trembath) forged relied on your experience and background in business," he said.

"You now realise you have been betrayed."

Trembath was handed a suspended sentence of 18 months, and released on $2000 recognisance and immediately released.

Australian Associated Press