The Dail has passed emergency legislation to ban the possession of certain drugs.

The legislation will go to the Seanad today and will then be sent to the President to sign into law.

The move comes after the Court of Criminal Appeal ruled that a law banning the possession of over 100 drugs, including ecstasy and so-called head shop drugs, was unconstitutional.

The ruling related to the Misuse of Drugs Act 1977, and specifically the powers of the Government to control substances which are harmful to health under section 2 of the Act.

It came about after a man challenged his 2012 prosecution for possession of the drug, methylethcathinone. Three judges in the Court of Criminal Appeal ruled that a regulation making the possession of the drug illegal was invalid as it was unconstitutional.

However, this ruling also covered other drugs in the same category as methylethcathinone, making their possession temporarily legal.

The emergency legislation was brought forward by Health Minister, Leo Varadkar, to make the possession of these drugs illegal again.

"We had no way of knowing what the Court would decide, but we prepared for this possibility. Legislation was prepared and approved in advance by Cabinet. The emergency legislation I am introducing will re-instate the status quo and and re-control all drugs that were controlled prior to this judgment," explained Minister Varadkar.

Meanwhile, the Department of Health emphasised that the outcome of this case ‘does not affect existing laws regarding the supply, possession or sale of older drugs such as heroin, cocaine or cannabis'.

However, it is expected that a number of convictions related to the newer drugs in question will be open to challenge following the Court's ruling.