Canberra has become the first city in Australia to legalise cannabis for personal use.

The bill was passed in the ACT Parliament on Wednesday afternoon after getting support from labor and the Greens.

Canberrans over 18 will be allowed to possess 50g of cannabis and grow two plants.

A household can only have four plants total and hydroponic growing will remain illegal, The ABC reported.

Politicians in The ACT are pushing for the legalisation of cannabis for personal use, which would allow people to grow two plants and hold up to 50 grams of the drug (stock image)

The law change will not come into effect until January 31.

ACT Health Minister Rachel Stephen-Smith must also sign off on the bill.

The private member's bill was introduced by Labor backbencher Michael Pettersson.

While legalising the drug might clash with federal drug laws, Mr Pettersson on Tuesday said he was 'very confident' there wouldn't be any problems.

Federal Attorney-General Christian Porter said the bill was a matter for the ACT, but where Commonwealth laws applied they remained enforceable.

Amendments made to the original bill require cannabis to be kept out of reach of children, and barring adults from using it near children or growing it in community gardens.

Mr Pettersson said his motivation for introducing the bill was to make drug use a health issue not a criminal one.

Residents of the bush capital wouldn't be able to light up immediately, with the ACT's Health Minister needing to sign off on when the law would come into effect (stock image)

'Because of our drug laws, getting caught with a small amount of cannabis can ruin your life,' he said.

He said it would be a waste of the federal government's time to strike down the law.

But it wouldn't be the first time laws introduced by the territory have clashed with federal laws.

In 2013, the capital legalised same-sex marriage only to have the federal government revoke the law after it took a challenge to the High Court.

Before that, in 1995, the Northern Territory legalised voluntary euthanasia only to have the federal government later legislate to stop the nation's territories from specifically introducing assisted dying.