Mandatory minimum prison sentences will do little to deter the gang activity plaguing cities across Canada, says a prominent criminal lawyer on the eve of a federal announcement of new anti-crime legislation.

The new bill, which Prime Minister Stephen Harper will announce in B.C. on Thursday, will reportedly contain mandatory minimum prison sentences for drive-by shootings and some serious drug offences.

It is also expected to include an automatic first-degree murder charge for gang-related killings.

However, Julian Falconer said Wednesday that mandatory minimum prison sentences are a misallocation of public funds.

"The truth of the matter is that there is very little, or any, criminological data that suggests they work," Falconer said during an interview on CTV's Power Play.

"The reality is that the only people that generally respond to this form of deterrence are your more opportunistic -- what one would call less-organized -- offenders. For your highly-organized offenders, your hardened thugs, there is no evidence that that form of deterrence works."

The new legislation comes at a time when B.C.'s Lower Mainland is experiencing a spike in gang activity. More than a dozen shootings in the past few weeks have led to a handful of deaths.

Oddly, while Harper visits the West Coast to speak about the upcoming legislation, two B.C. cabinet ministers will travel to Ottawa to lobby for tougher anti-gang laws.

Attorney General Wally Oppal and Solicitor General John van Dongen will meet with federal Justice Minister Rob Nicholson on Thursday to request tougher sentencing, disclosure and surveillance laws to fight gang activity.

Enforcement or punishment?

While the federal opposition parties said Wednesday they would likely support the new legislation, opposition MPs called for the government to do more to prevent crime.

"By all means punish the thugs that are wreaking havoc in communities causing death," NDP MP Olivia Chow said on Power Play. "But what the New Democrats want is to catch them before they kill and maim. Aside from punishment we have to do the enforcement."

Chow said the 2,500 new police officers the federal government promised for municipalities across the country have yet to be hired.

But Dave MacKenzie, parliamentary secretary the public safety minister, responded by saying that the RCMP has hired 1,600 new constables, more than the target of 1,000 new hires.

"This (gang activity) is not isolated to one part of the country," MacKenzie said. "It's major stuff. I think the legislation we're bringing forward will go a long way to helping the police and the prosecutors and the judges in their job."

According to Falconer, more money needs to be spent on prison rehabilitation and reintegration services, as well as programs to keep youth out of gangs.

"I'd ask the question, when we talk about gangs and gang activity, we have to appreciate that many of the individuals that make up these gangs are youth that are being recruited from the streets," Falconer said. "Disenchanted youth, and there are ways of trying to re-integrate and bring people back in the fold that aren't completely lost."

With files from The Canadian Press