Subcontractors have contacted the Enquirer about unpaid bill claims and one specialist staged a recent demonstration at an nmcn office.
Photos posted on social media show a poster hung on the railings of an nmcn office accusing the company of not paying subcontractors.
A cladding contractor told the Enquirer that it was owed £350,000 for a job completed last year.
The firm said: “They have been doing all they can not to pay us and it shouldn’t be allowed to happen.”
The Enquirer understands the bill has now been settled as nmcn apologised to suppliers for late payments.
The company is predicting a pre-tax loss of £22m for 2020 following problems identified on a series of contracts.
Nmcn is currently working with debt specialist Arrowpoint Advisory to arrange a finance package secured against the company’s property development projects.
A spokesperson at nmcn said: “Further to our recent RNS announcements, we are currently in the process of securing new investment.
“We are resolving the situation as quickly as possible and apologise for any payment delays experienced.
“We remain fully committed to our supply chain who are essential in delivering our strong pipeline of work.”