The Minister for Justice has asked the Garda for a report on the alleged incident in which people injecting heroin on Dublin's streets close to gardaí were not arrested and searched.
Mr McDowell said yesterday there was serious cause for disquiet if the report was true. He has asked the Deputy Garda Commissioner, Mr Noel Conroy, for a report on the matter.
Fine Gael and Labour yesterday called for greater drug treatment facilities and tougher police action after the Irish Independent published photographs of people using heroin in Temple Bar, apparently unhindered by gardaí nearby.
The Fine Gael spokesman on community, rural development and the Gaeltacht, Mr Fergus O'Dowd said the photos "highlight the urgent need to address the drugs problem in the capital.
"There are 13,000 drug addicts in Dublin, 50 per cent of whom are not receiving any treatment".
He said the €16 million seized by the Criminal Assets Bureau under the Proceeds of Crime Act since the bureau's inception in 1996 should be ring-fenced and allocated to fund drug treatment and awareness programmes.
"Since 1996 the CAB has seized €16 million in assets under the Proceeds of Crime Act, and these monies will be released into the central Exchequer next year, seven years after the Act was passed. Already the CAB has acted as an arm of the Exchequer and has earned the Exchequer another €42 million that reverts straight back to a central kitty.
"If the same is not to happen to this other €16 million then an amendment to the current legislation will have to be introduced now or the money will just slip away."
Labour's justice spokesman, Mr Joe Costello, called for "stricter law enforcement in tandem with increased drug rehabilitation facilities. To anyone with any knowledge of life on the streets in the centre of the capital, these pictures can hardly come as a huge surprise.
"However, the sight of gardaí standing beside the young men as they shoot up is alarming. It is unfair on residents and businesses in the area that the gardaí adopt a nonchalant attitude to such behaviour.
"That a simple word in the ear and a request to move on has become the way to deal with heroin-users is a shocking example of how drug abuse is an everyday crime."
He said that last month the Merchants Quay project in Dublin, the largest drugs treatment centre in the State, claimed it had suffered an effective cut in public funding, despite the fact that the numbers using its facilities were on the increase, and that it estimated there were 30,000 heroin-users in the city.
"Heroin abuse is not confined to the inner city or housing states. It is a curse that runs throughout society. Stricter enforcement by the Garda and improved resources for facilities and education to wean addicts off must be implemented immediately," Mr Costello said.
The Green Party spokesman on justice, Mr Ciaran Cuffe TD, said the focus should be on social and economic disadvantage.
"Better housing conditions, education and youth facilities are required, as well as proper policing," he said.