An aviation maintenance firm chaired by rock-star Bruce Dickinson is in dispute with the Welsh Government over the non-payment of rent.
An official has told an assembly committee that Cardiff Aviation, which has leased a hangar at St Athan from the administration since 2012, has not paid rent for it to date.
The Welsh Government is seeking legal advice over recovering the outstanding debt, a letter says.
The company says talks are ongoing.
It is not known how much the rent is worth.
Mr Dickinson previously told BBC Wales that his firm was losing millions of pounds because of a dispute over landing rights.
The Iron Maiden front-man set up Cardiff Aviation in 2012 at RAF St Athan, Vale of Glamorgan, leasing a hangar called Twin Peaks from the Welsh Government.
Welsh Government small business subsidiary Finance Wales has invested £1.6m.
A letter from Simon Jones, director of transport and ICT infrastructure, to the assembly's Public Accounts Committee chairman Nick Ramsay said that, "to date", Cardiff Aviation "has not paid any rent for their use of Twin Peaks".
"The company has put forward a number of reasons for not doing so," Mr Jones said.
"The Welsh Government disputes the basis for the non-payment, and we note that other companies operate from St Athan successfully without any issues.
"The Welsh Government is currently seeking legal advice regarding potential remedies and the recovery of the outstanding debt."
A spokesman for Cardiff Aviation said: "We have a good relationship with the Welsh Government and discussions are ongoing which we hope will promptly deliver productive outcomes for all parties."
A Welsh Government spokeswoman said: "We have been in ongoing discussions with the company for some time about this complex case.
"For legal reasons we will not be commenting in detail at this stage.
"The Welsh Government is currently investigating all options to protect the taxpayer interest and resolve this issue."
Responding, Public Accounts Committee chairman Mr Ramsay stated: "This response clearly raises as many questions as it answers.
"The Welsh Government are understandably concerned about the lack of payment and the public need to have an assurance that public money is being well spent.
"We will be considering this as a committee at the earliest opportunity."
Plaid Cymru AM Neil McEvoy, who raised questions about the company in the committee, said the situation raised serious questions about the "competence" of the Welsh Government.
He said: "It seems that they just don't know what they are doing."