A €1m review of Ireland's notoriously patchy road signage has been underway for more than six years, it has been confirmed.

A comprehensive revamp of the 'Traffic Signs Manual' began in 2004 but is not now expected to be published until the end of the year. Authorities have insisted there has been no undue delay in the project and that the review required new legislation.

The existing manual – published first in 1996 – was out of date and out of line with "international best practice", a statement said.

The Department of Transport ordered a review and redrafting of rules for signage, which was sub-contracted to a consultancy firm.

Fine Gael TD Simon Coveney said: "The idea that it would take six years to come up with a traffic signs manual seems extraordinary to me.

"I can also guess why it took that long but certainly it sounds like a report that was left half-finished for a long time. If something is not ready this much time later, there are clearly problems with how it is being managed and whether it is a priority.

"This should be bread and butter for the Department of Transport, the National Roads Authority (NRA) and the local authorities involved.

"It is something that needs updating. While the signage on motorways is of a very high quality, there is still major confusion over speed limit signage around the country."

The NRA confirmed it had hired a consultant to carry out the review, with that work overseen by a steering group. A statement said: "The update included a very significant review and upgrade of [a chapter on] ... signs for roadworks to take into account new health and safety legislation and much-enhanced safety measures that have been developed."

The review of signage at roadworks was the most complicated part of the work and a first revision of it was published in November 2006.

Almost two years of feedback from city councils, county councils, the NRA and other bodies saw another draft prepared in October 2008.

A final draft of the document was then prepared and it is understood a final version is due for publication later this year.

A statement said: "The update also included significant enhancements of the section on directional signage, to bring the manual up to date with best international practice, with considerable emphasis on overhead gantry signage on motorways and dual carriageways.

"A chapter on variable message signs which was not covered in the previous manual is also included in the updated manual."

A spokesman for the NRA said: "This project was a requirement of the Department of Transport. There is an existing traffic manual and this is simply a project to update the existing one."

It said that the cost of the project so far had come to €956,800, mainly made up of professional fees and printing costs.

The statement said: "It should be noted that a typical timeframe for a complete review of a traffic signs manual in other jurisdictions is usually in the order of five to 10 years."