The owner of Worcester-based Coghlin Electrical Contractors, which worked on the Encore Boston Harbor project, claims it is owed $30 million in last-minute work performed ahead of the $2.6 billion Everett casino’s opening.

Owner Sue Mailman said the company has not paid about $30 million in change orders. Mailman told MassLive that Wynn Resorts and Suffolk Construction, the primary contractor, have reviewed the larger change orders every six to eight months, rather than reviewing them every month.

“It’s choking my company," said Mailman, the fourth-generation owner of the family business. "It is definitely impacting my company.”

Encore opened June 23, a Sunday morning, after a three-year construction project. Wynn Resorts employed more than 7,000 construction workers to build the 3-million-square-foot casino along the Mystic River.

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The dispute, first reported by the Boston Herald, dates back several months as Mailman’s attorney sent letters to the Massachusetts Gaming Commission.

In a June 11 letter, Massachusetts Gaming Commission attorney Catherine Blue wrote she and the commission’s project oversight construction manager will “continue to monitor the progress of discussions between Encore Boston Harbor and Suffolk Construction regarding any unpaid subcontractors, and I will bring any concerns raised to Encore Boston Harbor for their review.”

Blue also wrote that Encore reached out to the contractor, Suffolk Construction. The contractor requested additional documents from Coughlin and proposed meeting dates to discuss the matter.

In a statement, Wynn Resorts said it has paid all invoices related to the Encore project to the contractor, Suffolk Construction.

“Subcontractors work directly with the contractor, not Encore Boston Harbor. Encore Boston Harbor has no outstanding invoices with Suffolk Construction,” the company stated." The relationship between Wynn Resorts and Suffolk has always been cordial and professional."

Suffolk Construction spokesman said that, “Suffolk continues to work directly with its subcontractors to resolve any outstanding legitimate issues. We are optimistic we can achieve satisfactory conclusions to close out a successful project.”

Mailman said her company initially signed a contract for $50 million in 2017, and had at least $14 million in change orders approved. She said there is $30 million outstanding, which she said was a legitimate issue.

Mailman said that on other projects, including the MGM Springfield construction, the owner and subcontractor would review change orders on a monthly basis.

“These are economic development projects for the state ... and if we achieve the goals of tradespeople coming into the unions, that’s awesome,” she said, referring to Wynn Resorts’ goals of hiring a diverse construction team, “but if locally owned subcontractors are financing these jobs and are hurt on these jobs, then we have not achieved our goal.”

McDonagh, the trade association CEO, said he believes it’s both Wynn Resorts’ and Suffolk Construction’s responsibility to make sure the change orders are approved and paid.

“They can’t wash their hands of this and say it’s not their problem,” McDonagh said.

This dispute is the latest of several bumps the Las Vegas company faced on the road to opening day. Wynn Resorts faced a suitability investigation after sexual misconduct allegations surfaced against then-founder Steve Wynn. Wynn denies the allegations but stepped down from the company. He did not agree to an interview with regulatory investigators.

The commission fined Wynn Resorts $35 million and CEO Matt Maddox $500,000 after investigators found that the company had tried to hide the allegations from regulators in Massachusetts and Nevada.

Wynn Resorts ultimately paid the fine, but not before rocking the regional gaming industry with news of talks with MGM over a possible sale of the Everett casino. The news outraged mayors in Everett and Springfield, which has a casino run by MGM. Massachusetts gaming law states that a company cannot own or operate more than one casino in the state.

Mass. regulators did not delve into the matter during the commission meeting Thursday morning. The five-member commission voted to approve Encore Boston Harbor’s permanent operations certificate with conditions to make certain fixes in the short-term.