The family of bankrupt former billionaire Seán Quinn has begun a legal action against the former Anglo Irish Bank, to stop assets being sold off or taken into NAMA.

The five adult Quinn children and their mother are suing the bank, claiming they are not liable for €2.3bn in loans given by Anglo to Quinn companies.

The family says the loans were given for the unlawful purpose of propping up the bank's share price.

That case is on hold pending the outcome of criminal proceedings against former Anglo executives.

But the Quinns say they need to take this action to protect the Quinn group assets.

The family says the assets are due to be sold off or transferred into NAMA by the end of the year as part of the winding up of the Irish Bank Resolution Corporation.

They say if they do not take this action, they will not be able to recover the assets if they eventually win their main action against the bank.

Lawyers for the Quinns indicated that if they are not successful, they may challenge the constitutionality of legislation winding up the IBRC.

Senior Counsel Martin Hayden said the legislation appeared to allow the State to appropriate citizens' assets without due process.

The Quinns allege they are the true owners of the assets and that the assets should have remained in their ownership.

The application is being strongly opposed by IBRC. The bank is likely to argue that the Quinns have no right to claim ownership of the assets and also that the assets have no real value because of debts owed by former Quinn companies to banks and bondholders.

The action is expected to last at least three days.