Legislation, including the 5k travel restriction is contained in
S.I. No. 121/2020 - Health Act 1947 (Section 31A -Temporary Restrictions) (Covid-19) Regulations 2020
Yes, I'm well aware of that. And of the three subsequent SIs that amended it. There are a couple of problems though.
Firstly, the government keeps contradicting what's in the SIs. The classic example being the over-70s. Also the concept of a necessary journey.
Second, the Government are remarkably slow to publish the SIs. Typically, they're not published until some time during the day they're actually in force. This leads to the remarkable situation that citizens have no way of knowing what the law actually is! Statements by ministers explaining the yet unpublished SIs are invariably misleading. Journalists are worse than useless and confuse matters even more.
When the SI is eventually published, it claims to have been made a few days previously. If this is the case, why was it not published at the time of making?
Thirdly (and on fairness this is a problem with much Irish legislation) the SIs are now very hard to follow. Later SIs amend earlier ones, sections are added and deleted, and, to work out what is and is not permitted, would require having both documents open and extensive cross referencing between them. It would have been much simpler to make and publish a consolidated version of the Regulations.
Putting it all together, it seems like there is a deliberate policy of muddying the waters and making it difficult or impossible for citizens to know what the law is. This is just wrong in principle and is undemocratic in nature.