The chief executive of Ryanair has said he will not let the Labour Court impose conditions on his company.

The Irish Airline Pilots Association (IALPA), a division of IMPACT, is taking a case to the Labour Court that could see a binding ruling being made in relation to the training of Ryanair pilots. The union is using an industrial relations law introduced this year. Mr Michael O'Leary described the 2004 law as "unconstitutional".

The IALPA case is being taken under the Industrial Relations (Miscellaneous Provisions) Act 2004, a measure which emerged from discussions between the social partners on the issue of union recognition.

Mr O'Leary said there was no way "a third party like IMPACT is going to use a third party institution like the Labour Court to impose a condition on a multinational like Ryanair using an unconstitutional piece of legislation... It's not going to happen."

He said his company did not recognise IMPACT and the union had no business making any representations to the Labour Court on behalf of Ryanair pilots.

He said it would be "beyond our understanding" if such a development could occur. "You may as well close down all the multinationals in the country... if the Labour Court is going to be able to impose conditions".

Mr O'Leary said that at the time the new legislation was being created it was agreed that it would not impose trade union recognition on multinational companies with highly paid employees.

"We will not be accepting any interference from any outside body like the Labour Court." He said that Ryanair, like many of the US multinationals that operate here, did not recognise trade unions.

The case initiated by IALPA centres on the right of pilots to be trained to fly new aircraft bought by Ryanair prior to the company employing new pilots to fly them.

If the Labour Court was to side with the union and the company did not engage in the process, then the court ruling could become binding under the Act.

At the time the legislation was passed, it was generally felt that it was likely to be used against indigenous small and medium sized companies or employers. However, a case has since been taken involving the Communications Workers' Union and telecoms company Meteor.

A spokeswoman for the US Chambers of Commerce in Ireland said she did not wish to comment on the legislation.