The singer insisted the drug helps him cope with fame and is no worse than alcohol.
He called for a more tolerant attitude to cannabis by authorities across the world before admitting it CAN cause problems for some users.
His comments were blasted by a top drug expert who claimed they could encourage more youngsters to dabble with the drug.
Old enough to make their own decisions
Nutini, 27, of Paisley, Renfrewshire, also backed boy band One Direction after their dope smoking scandal and blasted singer Miley Cyrus for her stage antics.
He said band members were old enough to make their own decisions after footage of members Zayne Malik and Louis Tomlinson apparently smoking a joint emerged.
But self-confessed marijuana user Nutini has lent his support to the under-fire stars and pointed the finger at singers such as Cyrus a worse influence.
Asked in an interview with music magazine Q if he smoked pot, the Scots star replied:
“Every day since I was about 16.
“Can the world please get to grips with marijuana? How long can this go on? Don’t get me wrong, you can give it to the wrong person, marijuana can spawn all kinds of things, but no more so than alcohol.
“Most nights out I can buy 20 Jägerbombs, take them away on a tray, for all they know I’m necking 10. People have been saying this s*** for 40 years.”
Could tempt youngsters
Professor Neil McKeganey, of the Centre for Drugs Misuse Research at Glasgow University, warned that his comments could tempt youngsters into experimenting with pot.
He said: “He has clearly failed to understand the terrible impact drug abuse has had throughout Scotland and particularly in the community from which he comes.
“Paolo is a fantastic musician, but when it comes to drugs he’s just another pop star on pot.
“It’s grossly irresponsible for him to be effectively advocating for young people to use cannabis.
“It’s quite likely that comments from someone who has his celebrity status, who is revered by many young people, could have a hugely negative impact on encouraging young people to smoke cannabis.
“He needs to become an ambassador to stay away from drugs, and not a figure of drug abuse.”
Prof McKeganey also warned the singer could be suffering from side effects caused by long-term drug use.
He said: “We know it substantially reduces intelligence and it also affects areas of the brain associated with judgement and can lead to an increase in serious mental health problems.
“If he has been taking cannabis for as long as he claims, he may well already be experiencing some of the psychological effects of extended use.
“And you don’t have to be using all the time to suffer intellectual and judgemental effects.
‘That is a dangerous misunderstanding’
“His celebrity status and musical accomplishments, in a way, now become aligned to his drug consumption, and young people may feel that if they take drugs like him they may reach the heights that he quite rightly reached as a result of his music.
“And that is a dangerous misunderstanding.”
Talking about One Direction, Nutini said: “They are men now. Let’s flip it and look at the female global pop stars out there.
“Sexualisation isn’t the problem, it’s a case of class. I saw a photo of Miley Cyrus with her leotard pulled up - is that cool?
“And One Direction can’t have a joint? They’re the bad role models? Come on.”
Tory MSP John Lamont also blasted the star for setting a bad example to young fans.
He said: “Paolo has to realise he’s a role model for many and this kind of remark can be extremely damaging.”
Police Scotland warned there was ‘no safe way to take drugs’.
A spokesman added: “Everyone needs to be aware of the short and longer terms dangers.
“You can never be sure of what you are taking or what effect it could have on you.”
“Rewind” singer Nutinin has previously told how he took a four year break from music and stepped back from the limelight after struggling with the pressures of fame.
The star said he recovered his love for music by going for walks in the Highlands and learning survivalist techniques.
Nutini has also said his meteoric rise to fame put immense strain on his relationship with girlfriend of 10 years Terri Brogan.
He has also revealed the independence debate makes his blood boil.
He added: “It shouldn’t be about Scots versus anybody.
“It should be everybody versus Westminster.I think a lot of Scots have a real underdog mentality about what their horizons can be.”
Nutini’s new album “Caustic Love” has received rave reviews and the singer begins a tour of the UK music festivals this summer.
• We have been asked to point out that the Centre for Drugs Misuse Research is no longer at Glasgow University but is an independent research group.