A group representing activists arrested during the G20 protests in Toronto says it is "overjoyed" at a decision Thursday to dismiss charges against dozens of demonstrators.

Citing a lack of evidence, Crown prosecutors dropped charges Thursday against about 90 people, most of whom travelled from Quebec to Toronto and were put up at a University of Toronto graduate studies building.

Police raided the building on June 27 and arrested about 90 people, charging them with conspiracy to commit a criminal act.

"This latest about-face by the Crown constitutes an implicit admission of defeat; it shows how flimsy the charges are and how scandalously the police behaved during the security operations around the Summit," says a statement from the Anti-Capitalist Convergence, a Montreal-based group that co-ordinated transportation and housing for protesters.

The statement posted on the group's site said the arrests were "arbitrary and uncalled for, and were intended to terrorize" demonstrators.

The group also said charges have been dropped against three of its members who were "preventatively" arrested on June 26, and held for over 72 hours.

Civil rights groups have decried the heavy-handed action of police, who in some cases stood back while so-called Black Bloc protesters burned police cars and vandalized buildings, but in other cases held large groups of peaceful protesters for hours, with no clear explanation for their actions.

More than 1,000 were arrested during the G20 in July, but only 300 were charged.

At least 100 have now had their charges dropped altogether, but it isn't clear how many still have outstanding charges against them.

A number of people were arrested in the weeks and months after the G20 as police released images and video and asked for help identifying suspects.

As recently as Thursday, a 22-year-old Montreal man was picked up by police and charged with assaulting a police officer and breaking windows at a Toronto business during the G20 weekend.

The Anti-Capitalist Convergence said two of its members are among 20 protest organizers that were arrested and have been labelled as ringleaders of the June 26 demonstrations, and subjected to stiff bail conditions, including house arrest.