A long-simmering dispute between the city of Santa Clara and San Francisco 49ers has been reignited during the NFL offseason.

A leaked draft of an audit claims the San Francisco 49ers owe the city of Santa Clara hundreds of thousands of dollars for its use of Levi's Stadium. Mayor Lisa Gillmor, who pushed for the $200,000 audit, told the Mercury News that it affirms her suspicions that taxpayer money has improperly subsidized the venue's operations.

Under a measure approved by the city's voters in 2010, no public money or city staff time is supposed to be spent on the Levi's Stadium events. A leaked draft of the audit, conducted by the Harvey M. Rose firm, found that the Niners owe the city $424,349 for public safety staff time.

A contractual agreement caps public safety costs for the team at $1.7 million a year, with 3 percent annual increases. But according to the Merc report, the 49ers surpassed that limit every year, requiring the city's Stadium Authority—a City Council-run commission that oversees Levi's and leases the property to the NFL team—to dip into its discretionary fund to pay the extra cost.

The 49ers quickly tried to discredit the findings.

In a 10-page response letter, the team called the report erroneous, incomplete and riddled with half-truths.

"We are disappointed that the Stadium Authority spent $200,000 to produce a report that will only serve to further confuse the board and the public with erroneous information, incomplete and out of context half-truths, and outright misrepresentations," the team's attorney Hannah Gordon wrote.

The audit also found that the Niners could owe Santa Clara nearly $719,000 for letting cars park on a public golf course, one of five city properties used for event parking. The 49ers disputes that claim, too, saying the team actually overpaid for parking.

The audit recommends strengthening financial controls over the stadium lease. Click here to read the draft report.