TORONTO - Ontario dismissed calls Tuesday for a public inquiry into the controversial G20 summit in Toronto, saying it's up to the federal government to decide if the probe is needed.

A group of lawyers and civil libertarians joined the Ontario New Democrats on Tuesday to demand an inquiry 100 days after the gathering of world leaders and the accompanying protests that saw more than 1,000 people detained by police.

However, Public Safety Minister Jim Bradley said there are already several different investigations into the G20 and the so-called secret law the province passed governing police powers during the summit.

The G8 and G20 summits were federal events, said Bradley, so it's up to Ottawa to decide if a public inquiry is needed in addition to all the other probes.

"We have four separate inquiries going on at the present time," he said.

"I think that no doubt there will be some interesting information which will be forthcoming, and I leave it to the federal government to make its decision on a federal inquiry in light of the fact that this was a federal operation."

NDP Leader Andrea Horwath plans to introduce a bill in the legislature to create an independent commission that would examine the decision and actions of both the provincial government and police during the G20, provide a "fuller accounting" of how taxpayer dollars were spent, and investigate whether basic rights and freedoms were compromised.

It's true there are several separate reviews of the G20 currently underway, she acknowledged.

"Yet none of these have the mandate or the jurisdiction to ask the most fundamental questions, or to provide Ontarians with the answers they are seeking," Horwath said.

Howard Morton, a lawyer who defended the only person charged under the province's so-called fence law, and Graeme Norton, a lawyer with the Canadian Civil Liberties Association, urged the public to support the bill.

"The G20 summit was a profound and transformative event for civil liberties in Canada," said Norton.

"Indeed, the overwhelming police presence witnessed by Canadians during the summit was like nothing this country has ever seen."

The other reviews don't have "the force of law" behind them, Morton said. A full public inquiry is needed to get to the bottom of what really happened on the streets of Toronto last June.

What's at stake are the rights and freedoms of all Ontario residents, he added.

"The risk is the police will believe in the future that, 'Yeah, we may have gone a little overboard, but nothing really happened,'" he said.

"You need clear guidelines in this country and in this province and in this city about what the police can and cannot do, in terms of stopping people and demanding identification and demanding to know why you are where you are."

Police began to arrest people en masse that weekend after protesters using so-called Black Bloc tactics broke away from a peaceful rally and ran through the city's downtown core, smashing windows and burning police cruisers.

It's believed to be the largest mass arrest in Canadian history, surpassing even the October Crisis in 1970 when martial law was imposed. The vast majority of those detained were released without charge within 24 hours.

Federal opposition parties have also demanded that the Conservative government come clean on the details of the $1.2 billion in summit costs.

Two weeks ago, the government disclosed about $200-million worth of eye-popping expenses, racked up primarily by the RCMP and the Public Works Department, in response to a query by a Liberal MP.

The documents revealed that taxpayers shelled out more than $10 million for hotel accommodation and more than $5 million in vehicle rentals for the RCMP, $4.4 million for the notorious security fence and $439,000 on portable toilets.

Then there was $14,000 on glow sticks, $85,000 for snacks at Toronto's swank Park Hyatt hotel, $14,300 for bug jackets, $26,000 for mosquito traps and $334,000 for "personal outdoor kits" that included sun screen, insect repellent and hand sanitizer.

Taxpayers also forked out more than $60,000 for binoculars, more than $600,000 for computer equipment and more than $250,000 for cameras and video recorders.

The Auditor General is already examining security expenditures for the summits but the Opposition Liberals want her mandate expanded to cover all costs.