While presenting the Port Company's annual report, Connellan suggested that the PDs had withdrawn their proposal and commented that "no one" had ever talked to him about the possibility of moving the port. "When the PDs launched their view of moving the port we weren't even invited - we asked could we go along just to listen, " he said later.

Connellan based his suggestion that the PDS had backtracked on remarks in the Seanad on 27 June by PD transport spokesman Senator Tom Morrissey and Pat 'the Cope' Gallagher. The only official government line has been a statement by Gallagher in the Seanad that day that "there are no proposals to move Dublin Port from its current location". Morrissey said then that he concurred "with that sentiment", but that he would like "direction" given to Dublin Port.

The PDs still want change, Morrissey stressed last week.

The party is planning a oneday conference on the future of the port on 20 October, and this time around, there should be no misunderstandings. "We have sent an invitation to Dublin Port, " Morrissey said.

"We are not saying Dublin Port should move, " he said.

"We are saying commence the process of de-industrialising it and putting in place a world-class cruise terminal there. There will be 78 cruise ships coming in to Dublin this year." He cited the examples of Bilbao, Barcelona and Helsinki, which moved their ports from city centres, and of Hamburg, which has begun doing so.

The PDs want much of the land at Dublin Port to be used for residential development, and last year presented their new vision for the port lands called 'A New Heart for Dublin'.

"We could have modern family living, transport links, a bay usable by the people of Dublin, " Morrissey said. "We have been in discussions with Dublin City Council and we could have in excess of 50,000 living down there, not in apartments but in family homes."

The plan has been circulated to a range of stakeholders, he said. "The reaction has been one question: how do you make it happen?"

However it might happen, the proposal has its supporters. "Dublin Port needs to be a residential and office area that will be the engine of the economy for the next 40 or 50 years, " said Tom Coffey, chief executive of Dublin City Business Association. "Dublin Port is for heavy things like oil that should be piped into Dublin Airport. We should stop this 19th century attitude."

Coffey called for the port to be moved to Bremore. "We need the port to move, and we need to link in with the railheads and major new roads that need to be built, " he said.

"We need to do it now while it is greenfield."

With Dublin Port Company revealing last week that volumes rose by 6% in the first half of the year, a key theme was capacity contraint. The state-owned company's controversial proposal is to reclaim 52 acres of Dublin Bay land opposite Clontarf.

Connellan said it has prepared a planning application and applied for two separate foreshore licences. He said the company is "confident" that it can solve its capacity problems without outside resources.

On the Bremore question, Connellan said greenfield sites are "pretty difficult" to develop. He noted that Associated British Ports spend £45m ( 66m) on trying to develop a greenfield site at Dibden Bay outside Southampton. "Brownfield sites are easier to develop, " he said.

"There have been no studies carried out in Bremore to see if it is viable or not."

Clontarf-based Fine Gael councillor Gerry Breen, who has campaigned against reclaiming the 52 acres, called for a masterplan for the port. "It's the last land bank that could be redeveloped in the city. Maybe we will want a lot of residential down there, so it is critical that there will be a masterplan."

The multiple benefits of developing a residential quarter on the port lands would include boosting the finances of the city's public transport systems, Coffey suggested.

He also wants a boom built across the bay to protect the city from rising tides, with potential to run a road on top.

"We need to face up to the issue of how you run the city in 2050 or 2080, " he said.

It's not that easy to move a port, cautioned economist Paul Tansey, who warned that moving the port north could generate more traffic congestion because so much port traffic comes from within the M50. Half of port volumes are destined for within the M50.

"What probably needs to happen is to look at the efficiency with which the port site is used, " Tansey said.

"The problem is not immediate but if you're banking on the fact that the economy is going to keep growing you will have to start looking at port configuration."

Just-in-time delivery systems and containerisation have supplanted the need for so much warehousing land, Tansey said. "You're looking at where are additional ships going to berth, how are they going to be loaded and at what price."

Irish Exporters Association chief executive John Whelan also called for the Port Company to use its existing 260 hectares more efficiently. "Belfast has twice the amount of lands and deals with half the throughput, " said Connellan in defence of the port's performance. "You can always improve and we are constantly trying to improve our performance."

Whelan said the key question is not whether there is a port "up the road" in Bremore. The real need is to take a long-term look at the future of Irish ports, which account for 99% of Irish trade, he said.

"We have under-invested dramatically in Irish ports for half a century."

In September last year, government appointed a firm of consultants, Fisher Associates, to carry out a capacity study of Irish ports, and that report was delivered to the department of tranport in June.

Tansey called for a big picture view, for government to examine what is needed over the next 25 years and how to fund it. "We pay relatively little attention to the major lifeline we have with the rest of the world in terms of trade, " he said. "I don't think we give enough significance to the importance of major ports. We are infatuated with airports".