The Greens Party has announced plans to launch a $350 million buy-back scheme to reduce gun crime across the country.

Federal Greens Leader Christine Milne gave word of the plan this week, saying the national scheme would see a ban on the importation or possession of semi-automatic handguns combined with a 12 month buy back scheme.

The plan is largely focused on the violent streets of western Sydney where a spate of recent drive-by shootings and gun-related incidences have sparked widespread concern.

Cate Faehrmann, a Greens Senate candidate in New South Wales, said the parliamentary budget office had tallied the cost of the proposal, putting estimates at $350 million to encourage gun-owners to hand in their weapons.

Christine Milne says the idea has worked before, claiming “it's the one thing to buy back the guns from the Port Arthur Massacre calibre of gun, but you have to get rid of hand guns as well.”

Ms Faehrmann says there have been efforts in the opposite direction from gun lobbyists: “We've seen the Shooters party continuing to weaken our gun laws,” she said.