A transport company seeking lucrative contracts to run Adelaide's public transport networks has shared fake quotes of former Labor ministers in an apparent bid to assist the South Australian Liberal Government press its case for rail privatisation.

Key points: The quotes are believed to be from a fake online article about SA politics posted to a forum in 2014

The quotes are believed to be from a fake online article about SA politics posted to a forum in 2014 They were attributed to then Labor ministers Tom Koutsantonis and Stephen Mullighan

They were attributed to then Labor ministers Tom Koutsantonis and Stephen Mullighan The quotes were then cited in an email by a public transport operator to the current State Government

An email from Downer Group's manager of government partnerships Sasha Grebe was sent on July 2, 2019, the day after SA Transport Minister Stephan Knoll announced the outsourcing.

The email, obtained through freedom of information by Labor MP Tom Koutsantonis, included quotes which appear to have been sourced from a fake news article.

Keolis Downer — a joint venture between the Downer Group and Keolis, a French transport company — is a leading contender to operate Adelaide's tram services once the current State Government's privatisation plans come into effect.

Mr Grebe, who was Scott Morrison's communications director until 2017, sent the email to recipients including an official from Mr Knoll's department.

"These might be helpful," Mr Grebe wrote, going on to detail a series of quotes attributed to Labor frontbenchers Tom Koutsantonis and Stephen Mullighan in 2014.

The quotes — which were fabricated — state the former Labor government was considering a partial privatisation of rail services.

"We are currently exploring options where the Adelaide metro [sic] railway lines would be partly privatised," Mr Koutsantonis is purported to have said.

They appear to have originated in a fake newspaper article posted on April Fools' Day on two public transport online discussion forums "Wheels On Steel" and "Bus Australia".

A user going by the name 'Palpatine' later in the discussion thread claimed responsibility for the fake news.

"I wrote it. I used The Advertiser and the name of a journalist from The Advertiser to try and make it look authentic — which it isn't," Palpatine said.

"It is an April Fools' joke and nothing more."

Mr Koutsantonis said the company had conducted itself in a "deeply inappropriate" way.

Tom Koutsantonis wants the auditor-general to investigate. ( ABC News: Tony Hill )

He also said Mr Knoll should have referred the email to the probity officer for the tender process.

"The idea that the Minister just did nothing raises more concerns and more questions," Mr Koutsantonis said.

"Is doing nothing the right thing when a tenderer is contacting your office attempting to influence a political debate?

"Keolis Downer should not have sent these emails."

Private companies have until later this month to apply to run Adelaide's tram services.

Keolis Downer currently runs some of the city's bus services.

Government says it is a 'storm in a teacup'

Mr Koutsantonis said he intended to ask the auditor-general to investigate, but Mr Knoll dismissed the concerns.

"This tender process is following the appropriate probity procedures and this is just another pathetic attempt at a smear campaign from Mr Koutsantonis," Mr Knoll said.

Mr Knoll said he ignored the email and the tender process was being run by the Department of Planning, Transport and Infrastructure, at arms-length from his office.

There is no suggestion the State Government solicited the email from Downer Group.

Downer Group head of corporate affairs Michael Sharp said the company had a strong record of being "apolitical".

"Downer is a major provider of services to every State Government in Australia and we are actively involved in policy discussions about public transport," Mr Sharp said.

"Management was unaware of this communication that has come to light and it was not sanctioned or approved."

South Australian Infrastructure Minister Stephan Knoll. ( ABC News: Nick Harmsen )

Mr Knoll has previously been questioned by the Opposition about his relationship with Keolis Downer.

In June, shortly before announcing the tram and train service privatisation, he visited the company in Newcastle.

Mr Koutsantonis questioned whether the company had been given the inside running to get the contract.

"What kind of relationship does the Government have with Keolis Downer?" he asked.

Mr Knoll accused the Opposition of trying to create a "storm in a teacup".

"What Mr Koutsantonis is trying to do is just whip up fear and innuendo and smear in relation to this tender process," Mr Knoll said.