Mayor Bill de Blasio said Friday that his major concern about legalizing marijuana is that big corporations will take over the industry and exploit its “addictive” nature to try to hook kids, just like the tobacco companies.

“My great fear, I’ve said it before, is the corporatization of the marijuana industry,” de Blasio said on WNYC radio. He said he’s afraid weed companies will target children “with the goal of trying to hook as many young people as possible on marijuana for the profit of those companies.”

He added: “That has real ramifications for health and safety and that has to be addressed.”

A 2012 study published by the Mayo Clinic found that users of marijuana have a smaller chance of developing an addiction to the drug than users of alcohol or tobacco.

However, the study also found that teenagers were more likely to become hooked on pot than adults.

De Blasio made the remarks as he expressed concerns about racial disparities in arrests for low-level offenses, like marijuana smoking.

“I don’t expect in any way, or accept in any way, disparity in policing,” de Blasio told WNYC host Brian Lehrer. “If there is a dynamic where enforcement is different, neighborhood by neighborhood, because of demographics, we’ve got to fix that, we’ve got to figure out a way forward.”

Legalization advocates said he was blowing smoke.

“We’ve actually come up with a bill for New York that absolutely can work and address a huge number of the issues that people are raising, including the issues the mayor raised today,” said state Sen. Liz Krueger.

Krueger (D-Manhattan) said the legislation she is sponsoring would bar those younger than 21 from buying pot and ban companies from marketing to children.

And Melissa Moore, deputy state director for the pro-legalization Drug Policy Alliance, argued that legalization would actually make it easier to limit youth access to pot as opposed to keeping it on the streets.

“It’s clear that criminalization is doing immense harm to youth, especially for African-American and Latino youth,” she said. “If the concern is really about the children, then the current policy needs vast correction.”

De Blasio and Gov. Cuomo have softened their stances on recreational weed in recent weeks after Cuomo primary challenger Cynthia Nixon declared she would back legalizing pot.

Hizzoner also said he has reservations about sports gambling because it can be addictive.

“I’m worried about sports gambling, I’m worried about the fact that gambling addiction is a real problem,” he said. “I’m trying to talk about what Pandora’s box are we opening here.”