An Bord Pleanála has questioned the need for the Government's proposal to create a special body to fast-track planning applications for major public and private projects.
During a rare public appearance, the chairman of the planning board, Mr John O'Connor, said: "We are now doing 80 per cent of appeals within the statutory timeframe of 18 weeks and we are continuing to improve on that. We have a strategic target of 90 per cent within the 18-week period and we would hope to be achieving that pretty soon," he told RTÉ's Week In Politics.
Local authority and National Roads Authority (NRA) projects are also being dealt with faster, said Mr O'Connor, in remarks that will be taken as implicit criticism of the Government's plans.
"In relation to infrastructure, these were previously dealt with in other ways and there has again been a marked improvement, as borne out by a study carried out by the NRA."
The heads of legislation from the Minister for the Environment, Mr Cullen, to create the National Infrastructure Board should be with the Cabinet before Christmas.
Under Mr Cullen's proposals, the new board would be given charge of major projects "which are in the national interest" - although this could include both State and private developments.
Supporting the thrust of the proposals, NRA chairman Mr Peter Malone said there is a need to "urgently reform" infrastructural planning.
Speaking at a transportation policy conference organised by the Association of Irish Regions, Mr Malone said the regulations affecting the NRA and other semi-state agencies are "inhibiting the efficient and cost-effective delivery of infrastructure".
"Serious consideration must be given to a one-stop shop development-approval mechanism. An indispensable element of reformed procedures is that finality be brought to the development consent process and that a consent, once duly obtained, can guarantee that a project can proceed quickly to completion," he declared.
Rejecting charges that major construction projects always go over budget, Mr Malone said: "It is unrealistic to expect that major projects can always be brought in on time and within budget under the current regulatory environment."
The South Eastern Motorway extension to the M50 secured legal approval in October 1998, but legal actions still under way mean that completion is uncertain.
Legal challenges could equally affect the M3 Clonee-Kells motorway, even though that was approved by An Bord Pleanála after a 28-day oral hearing - one of the longest in the history of the State.
The NRA and Meath County Council are "determined to see off" challenges from people who did not take part in the planning appeal hearing, he told the conference.
Calling for a special High Court division to deal with planning issues, he said projects such as the M3 would "bring social and economic benefits throughout the country".
Although the NRA has completed 187 km of roads in the past two years and begun work on a further 155 km, Mr Malone said the level of activity must increase further if Ireland is to catch up on other EU countries.
He added that the Government must give the NRA multi-annual budgets. "The authority must await Budget day to learn what the Exchequer allocation to the roads programme for the following year will be. The uncertainty about funding levels and the stop-go environment this creates militates against the effective management and roll-out of the national roads programme."