Aer Rianta has unveiled its plan for a new €100 million runway at Dublin airport.

The new runway will run parallel to the existing main runway. It will be just under two miles in length and will include a number of taxiway strips linking it to the existing runway network.

Despite the project's size, it is understood its location - 1.7 kilometres north of the existing main runway - will not compromise possible locations for the mooted second terminal at the airport.

The project will be located within lands currently owned by Aer Rianta but nonetheless will affect parts of the local road network. The Huntstown to Forrest Little road may have to be closed requiring a new road linking Huntstown to St Margarets.

The scheme will also require an extensive new drainage system which would be serviced by a number of "balancing ponds" around the runway. And an unspecified number of trees in the locality will also have to be felled or reduced in height.

Plans for the new runway were released yesterday as part of Aer Rianta's public consultation process on the new facility. Aer Rianta has invited public comment regarding the proposal and on completion of that process next month will compile its environmental impact study.

A submission for planning permission will be lodged with Fingal County Council next year. If that planning application is successful, a detailed design for the project will be prepared and clearing of the site will commence in 2005. Construction will begin in 2006 and the runway is expected to be opened in 2008.

A spokeswoman for Aer Rianta said a plan for the new runway had been part of the Dublin county development plan for 30 years. She added the new runway formed a central part of Aer Rianta's efforts to cater for projected passenger growth at the airport.

At present, Dublin Airport handles around 15 million passengers per year but this is expected to grow to around 32 million by 2020.

As well as the additional passengers, Aer Rianta said the increased range of aircraft types using the airport in the years ahead would create a need for "substantially more runway capacity by 2008".

Ryanair chief executive Mr Michael O'Leary said his group was opposed to the new runway.

"It is another white elephant from Aer Rianta," he said.

Mr O'Leary denied there was a need for a new runway saying existing runway facilities at the airport were not currently congested.

"Gatwick airport in London handles 40 million passengers per year and it only has one runway," he said. "At Dublin airport we already have one and a half runways... there is no need for a new runway."

One of the existing runways could be extended for around €30 million, Mr O'Leary said. He also disputed Aer Rianta's costing of the project, saying it would cost around €200 million to build and not €100 million as stated by the airport's authority.

"They are building this to cater for direct flights to Australia even though there will never be direct flights. We are opposed to it and we will be objecting to it... it is a waste of money and there is no justification for it."

He added he would be very surprised if the project ever went ahead.

A spokesman for Aer Lingus said the carrier would seek detailed information on the costing of the new project before it made any statement.

"The airlines and the passengers always end up paying for these things... it is all about costs," he said.

Plans for the new runway were exhibited yesterday at the Great Southern Hotel at Dublin Airport where they will remain open for public inspection until November 2nd.

The plans will also be exhibited at Dublin Airport's terminal building at the departures level from November 11th to 15th. Information regarding the project can also be accessed at one of Aer Rianta's websites at www.dublinairport.com.