The Department of Transport has appointed a consultancy firm, Atkins, to determine if the Dublin Port Tunnel is being built to an adequate height.
The consultants are expected to report shortly, and their decision is expected to bring closure to the current dispute between Dublin City Council and some port-users.
Atkins, a subsidiary of a British firm of the same name, is to assess the possibility, cost and possible need for an increase in clearance height to facilitate taller lorries using the tunnel.
The decision to appoint independent consultants was taken by the Department after transport groups, including the Irish Road Haulage Association (IRHA) and the Transport Users' Group (TUG) at the port, complained that the proposed permissible height for lorries at 4.65 metres was too restrictive.
The consultants are expected to present their review and recommendations to the Minister for Transport, Mr Brennan, within weeks.
Members of the IRHA and the TUG have both insisted that significant numbers of large lorries arriving in Ireland from overseas will find they will not be able to use the tunnel.
However, the number of lorries is being strongly contested, with the city council insisting that the tunnel is being built to current Austrian standards which apply in nearly all European countries.
It claims that only parts of Britain and Spain allow for higher lorries.
The Dublin Port Tunnel was first mooted in tandem with the Eastern Bypass for Dublin more than a decade ago and was proposed initially by consultants Geoconsult Arup with a height restriction of 4.65 metres for lorries.
This was reviewed in 1996 after the decision in November 1995 to go ahead with the tunnel in the absence of the Eastern Bypass.
At that time the height restriction for lorries on the Republic's roads was 4.2 metres.
The clearance height of 4.65 metres was later included in the planning process. Work on the tunnel began in June 2001.
However, last year some of the companies and business people using Dublin Port claimed that 30 per cent of all lorry traffic in and out of the port would be too tall for the tunnel's clearance and argued that the clearance should be increased.
The council, however, insisted that these estimates were incorrect.
It said independent surveys carried out by the Dublin Port Company and the National Institute of Transport Logistics - one of which was completed this year - put the number of tall lorries at less than 2 per cent.
Yesterday the deputy city engineer and project manager in charge of the tunnel project, Mr Tim Brick, confirmed that Atkins, which has an office at Balgriffin in north Co Dublin, had been appointed and said the city council welcomed the independent review.
"We are happy to co-operate with this independent review because we think it will bring clarity and finality to the debate about the issue," said Mr Brick.
