It has been reported that our proposal for a National Stadium on the Manukau Harbour was conceived over a beer. A fellow architect rang and asked what were we drinking: he wanted some.

Many other comments have indicated great enthusiasm. When we and Mark Hall had that drink together, we didn't conceive the stadium option as such, just the need to find the ideal location. Is Eden Park the right answer, given the objections from neighbours and interested parties? Is the CBD waterfront, given the issues of congestion, scale, and availability of land?

Do these options offer a long-term vision or just answer the short-term needs of the Rugby World Cup?

Respected observers had articulated a number of interesting facts about various options. Town planner Rodney Davies highlighted the limitations of the Britomart railway station for handling crowds.

Urban Designer Barry Rae, in the Herald, estimated the stadium will generate the arrival of about 7000 cars, 400 buses and 40 trains. Congestion of this magnitude effectively doubles the population of central Auckland, and often, on Friday nights for example, at the same time as the working population is attempting to leave.

So given a clean slate, where would be ideal? We wanted an area with good access, available land, and potential for growth. We felt the stadium should be part of the vision for Auckland as it will be in 50 years time, not four. We felt it should be a National Sports Stadium, not just a rugby ground. For economic viability, it should cater for a number of sports, as well as concerts and cultural events. It should, as Trevor Mallard suggested, "act as a source of regional and national pride".

The new stadium should be easily accessible by car, train, and foot, without contributing even more to localised congestion. It should also be accessible to the thousands of supporters coming from south of Auckland and also be handy to the airport.

Extremely importantly, also, it should be in a location which would not offend existing residents and businesses. It should be acceptable to the surrounding population during the disruptive period of construction, and also during operations over the next 100 years. It should be a valued part of the urban fabric, rather than an imposition.

It should be in scale with the surroundings, rather than overshadow them. It should be something which people would be proud to look at, rather than something which blocked their view or connection with light and air.

These were our criteria. Consideration of the maps of Greater Auckland, and an awareness of the areas of future population expansion, carried out in conjunction with town planning and environmental engineering advice, led us to what we consider to be the only appropriate location: at the head of the Manukau Harbour.

Here is a site which is central to the motorway system, with good road links about 20 minutes' drive from downtown Auckland. It is adjacent to the main trunk railway line at a juncture with multiple tracks ideal for a station, and centrally located between the retail centres of Onehunga, Otahuhu and Mangere Bridge, and the new Sylvia Park hub. These contain restaurants, bars, hotels and motels. It is surrounded by under-used land, with low densities of occupation, and it is potentially available.

A stadium over the sea at this location, with pedestrian causeways linking to rail station, carparks, pedestrian harbourfront walkways, and other facilities, would become a dramatic icon for all New Zealand sports.

It could incorporate athletics track, convention and cultural facilities. Venues for other sports could develop on adjacent land, creating a sports "axis" linking to Mt Smart Stadium. The two stadia would share carparking areas and training grounds.

Over the next few decades, the city end of the Manukau will be transformed. It will become much more appreciated for its beauty and potential for waterside living.

A stadium over Mangere Inlet would catalyse growth, in the adjacent area and neighbouring town centres. The industrial uses would be regenerated and joined by commercial and residential; hotels and accommodation would begin to appear, and the water edges continue to be developed as people-friendly parks, cycle tracks and walkways. Water pursuits would be incorporated, including wakas, rowing and kayaking, as well as educational activities such as training camps, youth villages and cultural events.

Initial discussions with kaumatua of Tainui and Ngati Whatua indicate extraordinary support for the project and its potential. The stadium itself would incorporate public spaces and functions with dramatic views west towards the Manukau Heads.

Sunlight reflecting off the sea would animate the sloping sides of the bowl, making it an object of great beauty and lightness. Artificial lighting would make it a dramatic object appearing to float over the water.

The lack of nearby residential zones offers the potential of 24-hour construction, so increasing the possibility of completion in time for the Rugby World Cup. The distance to present or future residential areas also minimises disruption from concerts.

The fact that this option was dreamed up after an excited conversation over a beer doesn't diminish its value: it is a serious proposition that requires serious consideration.

* Pete Bossley is Chair of the Auckland Branch of the New Zealand Institute of Architects and was one of the principal architects of the Museum of New Zealand, Te Papa Tongarewa.

Barry Copeland studied at Manchester University and as a young architect worked alongside renowned British architect, Sir Norman Foster. He moved to New Zealand in 1993. He specialises in sports architecture.