Ireland's Criminal Assets Bureau has obtained a court order to seize more than 1m euros in cash and cheques discovered earlier this month.
Thomas Murphy is alleged to be a former IRA chief of staff
It was found by gardai during a big cross-border search of land and houses.
The search included the residence of the alleged former IRA chief of staff Thomas "Slab" Murphy.
The order was made under the Proceeds of Crime Act against Mr Murphy, his brothers Patrick and Francis and the company Ace Oils Ltd.
The firm has a registered office at Ballybinaby, Hackballscross in County Louth.
The order to appoint a receiver to take possession of euro cash and cheques and sterling cash and cheques was granted by the President of the High Court, Mr Justice Finnegan, earlier this week.
The head of the Criminal Assets Bureau, Detective Chief Superintendent Felix McKenna, said in documents supplied to the court that the cash and cheques were found in black plastic bags in a cattle shed owned by Patrick Murphy adjacent to his residence.
Access to the shed was through a gate on a road on the Northern Ireland side of the border which opened out on to a farm complex owned by the Murphys, the court heard.
Access from the southern side of the border was through a field registered in the name of Patrick Murphy's wife, Rosemary, the judge was told.
Detective Chief Supt McKenna said in the documents that the CAB had been investigating the Murphys "for some considerable time", and that Tom, Frank and Patrick Murphy had for the past 20 years been involved in the oil distribution industry, oil smuggling and money laundering activities.