B.C.'s Attorney General Wally Oppal says the NDP needs to stop demanding tougher laws for young offenders and then standing in the way of the legal reforms.

Oppal cited the case of a 13-year-old arrested in Vancouver earlier this week for allegedly slashing a man with a knife on the SkyTrain because the man refused to give him a cigarette.

Police say the teen has had 75 run-ins with the authorities in the past year but can't be held in police custody while awaiting trial because he is too young.

New Democrat MLA Mike Farnworth criticized the B.C. government, saying it's the sort of case that makes people lose patience with the justice system,

Farnworth said B.C.'s attorney general should urge the federal government to toughen the laws dealing with young offenders.

"I find it really disturbing that a 13-year-old can have 75 run-ins with the police, and clearly, red flags aren't being raised," he said.

But Oppal told CBC News Wednesday that B.C.'s Liberal government has repeatedly urged the federal government to amend the law so judges can keep young suspects in custody pending trial, but the federal NDP MPs have opposed the changes.

"You know, the only resistance we've had from that has been from the federal NDP, who constantly oppose any toughening of the youth criminal justice act," said Oppal.

All federal opposition parties opposed changes

In November 2007, the Conservatives proposed changes to the Youth Justice Act that would give judges more power to detain young people considered a danger to the public and impose longer sentences for violent crimes.

At the time, MP Joe Comartin, the NDP's justice critic, told the CBC that he was skeptical of the proposed changes.

"Denunciation doesn't work," he said. "We know that from any number of studies done around the globe."

Deterrence is not a principle that's viable either, he said, adding that if the Tories really wanted to do something, they'd be looking at prevention, putting more police officers on the streets and more programs in place.

But the federal NDP is not the only party on record opposing reforms of the Youth Justice Act.

During the September 2008 election campaign, the Conservatives once again promised to change the Youth Justice Act. Both the Liberal and Bloc Québécois leaders said they opposed the idea.

Liberals said the Conservative proposal won't make Canada safer and compared it to attempts in several U.S. states to impose harsher sentences for young people that they claim failed to reduce crime rates.

"It's the wrong approach," then Liberal leader Stéphane Dion said at the time.

Bloc Leader Gilles Duceppe also decried the Tory plan.

"This is the Republican way of the United States: more people in prison, more arms in circulation," Duceppe said. "I don't want to live in that society."

Unlike the NDP, the B.C. Liberals and federal Liberal Party are not part of the same political organization.