NAMA wants the jewellery from Mary McCabe, wife of developer John McCabe (inset), to help meet €20m in judgments against her.
The ring would be similar in size to the rock that is currently being sported by Hollywood actress Jennifer Aniston.
Jennifer's fiance, actor Justin Theroux, popped the question to the former Friends actress last August.
However, Jennifer's ring is slightly smaller than Mrs McCabe's -- Jennifer's is only an 8-carat ring, while it's claimed Mrs McCabe's ring is an 8.38-carat diamond ring.
NAMA believes Mrs McCabe's ring alone is worth more than €150,000, based on the opinion of a jewellery valuer, while Mrs McCabe had valued it, the bracelet and necklace collectively at some €140,000, Rossa Fanning, for NAMA, told the High Court.
Mr Justice Peter Kelly yesterday agreed to grant orders to NAMA appointing a receiver over the three items of jewellery of Mrs McCabe, of Rath Stud, Ashbourne, Co Meath.
When the judge asked barrister Alison Keirse, who was in court on another matter, how big a 8.38-carat ring was, Ms Keirse said she didn't know, she had never owned a ring that size.
Making the application, Mr Fanning said Mrs McCabe had refused to hand over the jewellery by January 18 last as sought by his client. NAMA was concerned, if it did not secure the orders sought, the jewellery may not remain in her possession.
A letter written to NAMA by a son of Mrs McCabe had alleged the agency was behaving unfairly in bringing court proceedings, counsel said.
However, he said, the position of NAMA and the taxpayer could be prejudiced if this jewellery was sold.
NAMA contended it was entitled to the jewellery to go towards discharging the substantial liabilities of Mrs McCabe, he added. Mr Justice Kelly said it was an unusual application but he was satisfied to make the orders sought. He noted two judgments for sums totalling more than €20m had been entered against Mrs McCabe last year and she had failed to disclose the jewellery in her first statement of affairs but did so in her second.
He also noted NAMA contended the jewellery was worth substantially more than the €140,000 value ascribed by Mrs McCabe.
He was satisfied it was reasonable to infer, unless the court interfered, the property may not be available to NAMA as it should be and, in those circumstances, he appointed Jim Hamilton, of BDO, as receiver.
He granted various powers to Mr Hamilton, including to take possession of the jewellery and to retain a valuer to value it.
Last October, John McCabe was ordered to repay amounts totalling more than €100m to NAMA arising mainly from loans to companies in his building group and his personal guarantees of loans.