The Irish state is to be sued by a leading humanist group over legislation which prevents it conducting outdoor wedding ceremonies in Ireland.

The Humanist Association of Ireland, described by the Irish Times as a leading organizer of secular weddings, is preparing the legal action.

The association says it is suing the Irish government over a ‘narrow and arbitrary’ interpretation of legislation, which has stopped it conducting outdoor ceremonies.

The report says the humanist group was granted the legal authority to solemnize weddings in late 2012 and is set to preside over more than 600 ceremonies in 2014.

But it is not allowed to conduct outdoor weddings for couples due to General Registrar’s "interpretation of the legislation which is so narrow as to not make any sense."

The Irish Times reports that under current legislation, all weddings in Ireland must take place at a location easily identifiable with an address and open to the public at reasonable times.

The association’s director of ceremonies Brian Whiteside told the paper that the Irish state’s current position is that this can only be a permanent structure.

As a result, weddings are banned in parks, gazebos, marquees, country house lawns and even hotel roof gardens.

Whiteside said: “It seems so arbitrary. There are a lot of country houses which have beautiful lawns, but we have to cram people into rooms which are not so suited.”

The group has engaged in written exchanges with the Irish government’s General Registrar in an effort to reach a compromise.

The General Registrar’s office has told the humanists that it insists on weddings being held indoors "to avoid situations where marriages are solemnized to which there may be an impediment, to prevent forced marriages, and to provide an opportunity for the making of objections."

It has not explained to the association how four walls and a roof could safeguard against such eventualities, according to the Irish Times report.