Dissident republicans are charging drug dealers a "licence fee" to operate in nationalist areas, Sinn Féin has claimed.
Dissident republicans have said they oppose drug dealing but they stand accused of charging dealers a "tax".
Senior republican sources say criminal gangs in north and west Belfast who call themselves dissidents are extorting tens of thousands of pounds.
It is claimed dealers are increasing the amount of drugs to pay the "tax".
One criminal in north Belfast was forced to help the Continuity IRA import 120kgs of drugs from Spain. He was then made to pay a tax of £90,000 to the organisation, republican sources have said.
At a briefing in west Belfast at the weekend, they told journalists that people living in the affected areas were being encouraged to co-operate with the police.
by Vincent Kearney
BBC NI Home Affairs Correspondent
Source - http://news.bbc.co.uk/1/hi/northern_ireland/7864365.stm