The former managing director of a company that completed millions of dollars of work for Metro Trains says he was told the rail operator was ‘‘awash with corruption’’.

The claim is detailed in a statutory declaration that also alleges employees who were ‘‘on the take’’ had been ‘‘gifted such things as jet skis and additions erected to their properties paid for by suppliers’’.

Mark Boulton, who headed Metro Trains supplier Vital Services Group from October 2012 until January this year, has detailed his allegations in a statutory declaration signed in March and seen by Fairfax Media. The statutory declaration was provided to Metro Trains as part of an internal audit into allegations of corruption and kickbacks.

The rail operator said on Sunday that an internal investigation team had examined the claims and concluded there was no evidence to support any wrongdoing by its employees.

Mr Boulton declined to comment when contacted on Sunday, saying only that he would take his claims to Victoria Police if a legal case against Metro Trains he is mounting came to nothing. ‘‘I will go to the police with my evidence if I don’t get satisfaction,’’ said Mr Boulton, who is understood to be involved in legal action against Metro Trains over alleged damage to his reputation.

In the statutory declaration, he alleges three employees of Metro Trains ‘‘conspired to obtain financial reward in return for offering subcontracting work to Vital Services Group’’.

Mr Boulton came to Australia in 2012 to head up Vital Services Group, which did maintenance work and provided track-side safety workers to Metro Trains.

Mr Boulton, like many senior railway managers now working in Melbourne, comes from Britain. He alleges a Metro Trains manager told him when he first arrived that the company was ‘‘awash with corruption’’.

That manager, the statutory declaration alleges, told Mr Boulton that ‘‘most of the foremen were ‘on the take’ and that some had been gifted such things as jet skis and had additions erected to their properties paid for by suppliers of Metro Trains Melbourne’’.

‘‘[They] told us that some had even created new limited companies to provide services to MTM, thereby making earnings out of MTM in addition to their salary,’’ the document stated.

The statutory declaration accuses a senior Metro Trains employee of colluding to set up a new company to ‘‘siphon’’ money from Metro Trains by ‘‘award[ing] labour hire and other work’’.

Mr Boulton said that - at one of a string of meals at Port Melbourne’s Railway Club Hotel - he was told of a Metro Trains employee who had been caught by an internal audit ‘‘setting up a supplier company in his own name’’.

Mr Boulton resigned from Vital Services Group in January after, his statutory declaration said, ‘‘the tap of work from Metro Trains Melbourne had almost been turned off’’.

The document was last week widely circulated within Melbourne’s rail industry. Among those to see a copy was Electrical Trades Union organiser Gerry Glover, who said there needed to be further investigation. ‘‘This is taxpayers' money,’’ he said, ‘‘so we need to know these allegations have been tested.’’

Metro Trains spokeswoman Leah Waymark said the allegations were very serious but the company’s extensive investigation had found no wrongdoing by those named in the document.

‘‘We have a whistleblower hot line in place and we actively encourage employees and suppliers who suspect inappropriate conduct to alert us for investigation,’’ she said.

Metro Trains’ investigation is understood to have included interviews, examination of transactions and receipts, and a check of the company’s IT system.

Despite this, the state opposition said the Napthine government needed to investigate because the rail system was publicly funded. Shadow public transport spokeswoman Jill Hennessy said the allegation ‘‘begs the question whether there is systemic rorting in the public transport sector’’.

Public Transport Minister Terry Mulder’s spokeswoman said the government had no knowledge of the matter but had been assured by Metro Trains that appropriate investigations had been undertaken.