High-profile developer Seán Dunne has invited his fellow property developers to join a powerful new organisation which will seek to dictate how the controversial National Asset Management Agency (Nama) will operate in relation to developer's loans and assets.

Nama is due to assume ultimate responsibility for up to €90bn of loans held by property developers in Ireland later this year.

Dunne is proposing the setting up of a body called the Irish Property Developers Federation (IPDF) to represent Irish developers in their negotiations with Nama. The body would meet with banks, the Department of Finance and planning authorities, and work closely with the Construction Industry Federation (CIF).

Dunne circulated an email – seen by the Sunday Tribune – asking developers to meet him and other developers on 2 May at the D4 Ballsbridge Court Hotel, formerly the Berkeley Court, which he bought along with the adjacent Jurys Ballsbridge and Towers Hotels for €380m.

Dunne said details were to be kept "private and confidential and not revealed to any members of the press". Admission was by invitation only. Dunne did not return a call last week seeking comment on the IPDF plans.

In the email, he said he was moving to set up the federation as he had been contacted by a number of property developers interested in establishing such a federation as a result of the proposed Nama. The CIF is aware of the proposal, he said.

The IPDF would be an autonomous body and represent "property developers solely while working hand in hand with other sections of the industry for the industry's benefit and future in Ireland". The initial joining fee would be €500.

Developers have been seeking legal advice on Nama in recent weeks and solvent developers in particular are seeking legal advice on ways to avoid having their assets transferred to the body as they are worried they won't have access to working capital afterwards.

If the IPDF gets going, the Department of Finance could end up negotiating with the group over billions of euros of loans and underlying property assets. Developers are threatening to take legal action over Nama because it is expected to have mandatory powers to strip loans from banks, along with their accompanying securities.

The government yesterday appeared sanguine about the legal threats and the establishment of Dunne's group.

Speaking to the Sunday Tribune, finance minister Brian Lenihan said: "We will not be deflected or delayed by obstructive legal strategies.'' He said Nama legislation had not yet been tabled, but he was confident the proposals would meet any legal challenge submitted by property developers.

"Of course individuals are entitled to seek legal advice from their representatives, but it's important we get progress on Nama so we can get credit flowing into the economy again,'' he said.