TORONTO -- Ontario is rallying other provinces and territories to put pressure on Ottawa to reconsider its decision not to ban generic forms of OxyContin, a highly addictive and much-abused painkiller.

Health Minister Deb Matthews says she also plans to bring in regulations that would limit access to the drug in Ontario unless it's tamper-resistant.

Under the proposed regulations, long-acting oxycodone products won't be considered for public funding or be substituted for the brand name drug by pharmacists unless they meet certain criteria.

The draft rules would also give the ministry the authority not to pay a dispensing doctor or pharmacy operator who doesn't comply with legislation aimed at tracking potential misuse and diversion of prescription narcotics.

Matthews says the regulations, which have been posted for public feedback, would be made retroactive so that they would come into force as of Friday.

OxyContin was meant to manage pain with a formula that released one dose of oxycodone over many hours. However, abusers could circumvent the timed-release feature by crushing the pills.

Matthews urged all the provinces and territories Friday to band together and convince Health Canada to reverse its decision and block generic forms of the opioid painkiller.

"I recognize that pain is a serious issue, and I am committed to working with patients and providers to better integrate pain management into our health-care system," she wrote Friday in a letter to her counterparts.

"But we simply do not need easily abused long-acting oxycodone drugs to achieve better care."

The move comes just a few days after federal Health Minister Leona Aglukkaq refused to interfere in the drug approval process to block generic forms of the drug, saying federal laws don't allow regulators to ban a drug simply because some people abuse it.

Provincial health ministers had unanimously requested that she at least delay approval until regulators can examine how oxycodone is abused. Ontario had repeatedly demanded that the drug be banned completely.

Aglukkaq's refusal to intervene opens the door for generic oxycodone to win approval in Canada after the patent for the brand-name OxyContin expires on Nov. 25. The manufacturer is now marketing OxyNeo as a replacement that is more difficult to tamper with.

Aglukkaq said in a statement that the regulations proposed by Matthews should also be applicable to OxyNeo.

"Considering there is no proof to date that OxyNeo is actually tamper-resistant, I assume her regulations will apply equally to OxyNeo as well," Aglukkaq said.

"Otherwise, she would appear to be playing favourites to one drug company, which I'm sure is an impression that she would not want to give."

Since Aglukkaq's announcement, doctors, pharmacists, First Nation leaders and police chiefs have expressed deep concerns about the decision, Matthews wrote in the letter, a copy of which was also sent to Aglukkaq.

"I am seeking your support in asking that Health Canada reconsider their decision, as this remains the single most effective way to prevent the devastating impact that this drug can have on our respective jurisdictions," she wrote.

Montana Attorney General Steve Bullock has also written to Aglukkaq, asking that the Canadian reconsider its position.

Bullock, who will be sworn in as governor in January, told the minister in a letter Wednesday that oxycodone will be easier to abuse and could undermine efforts to prevent addiction.

"Studies have shown that the tamper-resistant changes OxyContin manufacturers have made to the drug have resulted in less abuse among addicts," Bullock wrote.

"I have concerns that allowing easier-to-abuse oxycodone in Canada could undo some of the work that both Canadian and U.S. government and community leaders have accomplished in combating this epidemic."

Ontario has the highest rate of prescription narcotic abuse in the country -- two to four times higher than any other province, according to Matthews.

It has devastated many First Nations communities, including one small northern reserve where 85 per cent of residents are addicted to opioids.