The Nationalist Party on Saturday called on the government to withdraw the newly passed legal notice legalising the recreational use of cannabis, pledging to use "all possible Parliamentary means" to have it scrapped. 

A party spokesman said the legislation should be withdrawn until the necessary legal structures were in place to allow cannabis to be sold legally, which is not yet the case.

"Not only is Robert Abela not reducing the scope for trafficking, but he has just created the largest market that has ever existed," the PN said in a statement.

"This bill was opposed by the widest possible spectrum of organisations, and has now become law despite all the negative implications and the warnings of public and mental health experts."

The PN also criticised the government for introducing the law shortly before the Christmas festivities, when, it said, drug use was known to increase.

The bill, Legal Notice 478, was signed into law by President George Vella earlier on Saturday. 

With the law now in force, Malta becomes the first country in Europe to permit restricted use of cannabis for recreational use. As of Saturday, cannabis users can carry up to 7g of the substance on them without fear of prosecution and grow four plants at home. Any users who in the past were convicted of cannabis possession offences can apply to have their criminal records expunged.

Critics of the reform range from medical professionals to Church-run organisations and employers, as well as former prime minister Lawrence Gonzi and former president Marie-Louise Coleiro Preca, who have also made their concerns public.

The PN previously said it would seek to reform the law “based on data” if elected to government.  

The government has insisted the new law is rooted in “the principle of harm reduction” and urged people "to make the best choices for their wellness", committing to "programs of prevention against all substance abuses."