North Wales Police chief constable Richard Brunstrom has said he will be "campaigning hard" for drugs such as heroin to be legalised.
Richard Brunstrom wants support from the force's governing body
In the past, Mr Brunstrom has said drugs laws are out of date and that the police are engaged in a battle which they cannot win.
He is now campaigning for drugs to be legalised, and for the class A, B and C system to be scrapped.
Mr Brunstrom's suggestions have already been criticised by some politicians.
In a report to be presented to the North Wales Police Authority next Monday, he says the Misuse of Drugs Act 1971 should be replaced by a new "Substance Misuse Act".
The chair of the authority, Ian Roberts, said there would be a "full and frank debate" on the issue.
In the report Mr Brunstrom wrote: "If policy on drugs is in future to be pragmatic not moralistic, driven by ethics not dogma, then the current prohibitionist stance will have to be swept away as both unworkable and immoral....
"Such a strategy leads inevitably to the legalisation and regulation of all drugs".
His report was prepared in response to the government consultation paper "Drugs: Our community, your say", and the forthcoming Welsh Assembly Government consultation on the all-Wales substance misuse strategy.
The Transform Drug Policy Foundation (TDPF), which describes itself as a charitable think-tank and says drug prohibition is the major cause of drug-related harm to individuals, communities and nations, welcomed Mr Brunstrom's report.
Director Danny Kushlick said: "We are absolutely delighted at Mr Brunstrom's paper.
"The chief constable has displayed great leadership and imagination in very publicly calling for a drug policy that replaces the evident failings of prohibition with a legal system of regulation and control for potentially dangerous drugs".
But Alyn and Deeside MP Mark Tami said claiming the legalising of heroin as the only way forward was "blinkered and dangerous".
He said drugs policy was not "black and white" and a more considered approach had to be taken.
He said: "As 280,000 Class A drug users are responsible for half of all crime, taking the risk of legalising such a dangerous drug is foolhardy and I would not wish to gamble so much on the health and wellbeing of our children."
'Deprivation and poverty'
Alyn and Deeside AM Carl Sergeant said a more sustainable solution would be to tackle the causes of drug abuse.
He said: "Drug use is strongly linked to deprivation and poverty, which is why so much money has been invested in lifting people - particularly children - out of poverty."
Mr Brunstrom's comments came as Conwy Council's cabinet discussed plans for a needle exchange machine which the force want installed on the back of Colwyn Bay police station.
The cabinet voted to "take all necessary steps to ensure that the rights of this council are not infringed to gain public access to another building," which aimed to stop addicts crossing a strip of council-owned land to reach the machine.
Clwyd West Conservative AM Darren Millar called that "great news for the people of Colwyn Bay."
He said: "I hope North Wales Police will accept the decision and not waste more taxpayers' money challenging the advice that the cabinet has acted upon."
Asked whether a planning appeal would go-ahead, a police spokeswoman said: "We are not in a position to say anything yet because we haven't had all the information from the council meeting."
A council report warned that the police could allow addicts to pass through their own site in order to reach the machine to avoid any dispute about access with the authority.