In what is now a wasteland, soon the arias of Verdi and Puccini might sound. There's talk in the air about a national opera house to be situated in the former Dublin Gas site, around Grand Canal Harbour in Dublin.

The Dublin Docklands Development Authority (DDDA) is committed to building an arts/ culture complex on a two-and-a-half-acre site near Barrow Street, to open its doors late next year. Una Carmody and Joe Melvin, who have had extensive experience of urban renewal at Temple Bar Properties, were recently appointed to further the development. But, as a report has been commissioned to look at the various options for the site, it is clear that a national opera house isn't yet a foregone conclusion.

This is a story with a lot of interested parties. Opera Ireland, the Abbey, the Gaiety, the Wexford Opera Festival, the theatre and arts sector in general all have an opinion as to what should fill this, as yet, blank space. Behind the scenes, there is a push on for a grand opera house, something the DDDA does not yet favour above any other idea.

"This is still an open book," says Joanne Geary, marketing manager with the DDDA. She does say that "it's probably going to be in the performing arts line," although she urges patience until KSN Project Management come up with a recommendation for the space in their report, commissioned by the DDDA and due out next month.

Geary does express some support for the idea of an opera house: "it's something we would seriously look at," she says, "but we'd have to feel comfortable that it would attract large numbers of people on a regular basis." Others, like Judy Woodworth, director of the National Concert Hall, have their doubts. "I would be very aware of the costs in sustaining a full-time opera house in a city the size of Dublin," she says. "I would query the necessity for it to be dedicated wholly to grand opera. I feel that, for Dublin, a more flexible, multi-purpose performance space would be more suitable."

John Costigan, director of the Gaiety Theatre, is also critical of the opera house idea. In his view, the Gaiety could provide an adequate opera venue, for a fraction of the cost, leaving the proposed new complex free for another purpose.

"Before you start spending money on new theatre stock, you should look at the existing theatre stock. My view is that we need to upgrade the existing theatre stock," says Costigan. "As for a wholly dedicated opera house in Dublin, there's neither the audience for opera all year round, nor the resources to produce it. The only major opera produced in Dublin is produced by Opera Ireland, whose home is now effectively the Gaiety, and we're committed to an investment programme to refurbish the backstage, which will address their needs."

Yet the executive director of Opera Ireland, David Collopy, would welcome a dedicated national opera house. Indeed he has been calling for one for years. He adds that Opera Ireland would be interested in taking up residency in such a building, and, in his view, the audience for opera is growing exponentially.

Collopy does admit, however, that the new performance space would also need to stage events other than opera, as there is not yet the audience nor the resources to sustain year round grand opera.

Another idea that has been in circulation for some time is that the site should be offered to the Abbey Theatre as a new home. Their current 1966 building is in decline, and while the Abbey plans a major refurbishment, many, like Paul McGuinness, think that rehousing the Abbey should be considered.

"It would be foolish to look at the need for an opera house in isolation from the question of where the Abbey Theatre's going to be - there's a bigger picture here," says McGuinness. John Costigan agrees: "The Abbey should walk away from the old building and go to the new site and make something brand new for themselves."

But this suggestion is strongly opposed by the Abbey Theatre itself, where plans for a refurbished theatre on the current site are in train. As the theatre's managing director, Richard Wakely, argues, "it would be totally inappropriate to rehouse the Abbey in the new site. It would take us away from our historic roots in Lower Abbey Street."

Another option, and one that receives a lot of support from the Arts Council, is for the space to be given over to a mid-range theatre. In the Arts Plan 1999- 2001, the Arts Council's blueprint for the next three years, "the acutely felt absence of a 300 to a 450-seat subsidised flexible space in Dublin" was noted. As Michael Diskin, manager of the Town Hall and Black Box theatres in Galway, points out, the lack of such a space has very practical consequences for regional touring companies, like Druid or Red Kettle.

"If someone wants to tour a show in Ireland, I can tell them immediately who to ring in Cork, Limerick, Galway, Letterkenny or Mullingar," says Diskin, "but I can't tell them who to ring in Dublin. It's the most distorted infrastructure. At one end, you've venues like the Gaiety and the Olympia, which are commercial and very expensive. Then you have the Abbey, the Gate, the Project where you've very focussed artistic agendas. If you've got a hit show you just can't ring up the Abbey and say `hey, have you got a free week in November?' It doesn't work like that - but it works like that in the regions, and it makes an awful lot more sense that way."

Diskin argues that Dublin badly needs a mid-range municipal theatre, and says "an opera house seems like another great irrelevancy".

This on-going need for a midrange performance space in the capital is recognised by Patricia Quinn, director of the Arts Council. "In terms of what the needs are, we had a look at this about two and-a-half years ago and we really saw the need for a medium-scale lyric theatre, a theatre with a natural acoustic which can take theatre, but also music, opera or dance. There's a chronic need for a small to medium-scale, custom-built lyric theatre," she says.

While this need is widely accepted, it is clear that a building designed as a dedicated opera house could not double as a medium scale theatre. Not only does opera need a large orchestra pit, backstage area, and good acoustic, but because of the expense of mounting opera productions, it must also have between 1,000 and 1,500 seats to make it viable. KSN Project Management must find out if that amount of seating, as well as all the other requirements for opera, will fit into a complex which will only be about the size of the Irish Film Centre in Temple Bar.

If not, other options must be considered. A custom-made national opera house without a constant audience and a sustainable future would certainly turn out to be a white elephant.