A corruption probe has been launched into allegations that sex was being offered in return for lucrative State Government infrastructure contracts.

The Weekend West has obtained what appears to be an email between a female company boss and her secret male lover, who managed multimillion-dollar contracts on behalf of a major government department.

In the 2017 email, which the Premier has referred to the Corruption and Crime Commission, the woman talked about the “need to get a few things clear” regarding the “arrangement” the pair had.

“I don’t want or expect you to leave your wife,” it reads. “The way things are at the moment works well and we both get something out of it. I’m getting plenty of work and training opps, and you’re getting what you’re getting so let’s just leave it at that. I have booked a room at the Crown for Thursday night. Give me a call later.”

The man worked for a company subcontracted by the department to manage the tendering processes for more than $50 million worth of maintenance and smaller construction projects.

A spokesman for the department this week confirmed it was “aware of the allegations and is investigating”.

The Weekend West also has a copy of a letter from the Department of Premier and Cabinet, responding to a whistleblower’s concerns about the tryst.

“Thank you for your email to the Premier in regard to corruption within companies working as representatives of (department name deleted),” the letter reads.

“The department assessed the allegations in your email and as the allegations appear to represent serious misconduct under the Corruption, Crime and Misconduct Act, we will refer this email directly to the CCC. Thank you for taking the time to inform the Premier of your concerns.”

The anonymous whistleblower believed there were other misconduct issues that needed investigation, but would not elaborate.

“Given the content of the email, we find it highly inappropriate for taxpayers’ money to be used to get oneself sexual favours, as well as using sexual favours to get government contracts,” they told The Weekend West.

In the early-morning email between the pair, the woman apologised to her lover for not answering his telephone calls and said that if it was work related he should call the office.

“I don’t have time for anything serious,” she wrote. “We have talked about this. My career comes first.”