The Green Party leader’s call comes as documents released under the Freedom of Information Act reveal the Department of Communications went against the advice of a private consultancy company and a State-appointed postcode board when it approved the design of Eircode.

While the Department and Capita Ireland — the company behind the rollout of Eircode — has described the design of the postcode as “a world first” and “future-proof”, it has come in for criticism from a digital rights group, an association representing frontline emergency response staff, and a number of logistics and transport companies.

Eircode is a world first in assigning a random code to every address in the country, which its proponents claim will tackle Ireland’s high number of non-unique rural addresses. Critics however, claim it will be of less use to the public and to private companies as the random code does not identify clusters of addresses, a benefit of ‘hierarchical’ codes such as that used in the UK.

The National Postcodes Project Board, comprising representatives from government departments and public and private sector organisations, had recommended the adoption of a hierarchical code in its final report to the department.

Now, documents released under the Freedom of Information Act show that, in October 2010, months before the postcode project went to tender, PA Consulting Group issued a briefing note to the department in which it said it was its “firm recommendation that the conclusions and recommendations of The National Postcodes Project Board with regards to the format of the postcode continue to be followed”.

As communications minister, Mr Ryan announced plans to restart the postcode project in September 2009 and oversaw the process until he was replaced in February 2011 by Pat Rabbitte. Mr Ryan has questioned the design of Eircode and said a random code will be harder to remember and that it will be an issue for the public.

“It doesn’t just relate to how other haulage or transport distribution companies are going to use it, it also is an issue for the public,” he said. “A lot of people may be surprised when they get their code. If you’re in Limerick you would think you would get a code with L or LK and if it’s XZ you would wonder ‘what’s that got to do with where I am?’ ”

The department said that Capita Ireland rejected the use of hierarchical codes for a number of reasons.