Abbott supports NSW marijuana trial

Prime Minister Tony Abbott supports the NSW trial for medicinal cannabis but has dodged suggestions a national experiment should happen.

Children with severe epilepsy, terminally ill adults and those undergoing chemotherapy could be part of the $9 million trial to help alleviate their symptoms.

Mr Abbott said he had supported a practical trial all along, as did other premiers.

Preparations for the trial start this week.

Before it can get underway the NSW government has to overcome logistical hurdles in importing medical cannabis products from Europe or the US.

Approval for the importation of the products may take several weeks, but if permission is denied the NSW government has indicated it could grow its own cannabis crop.

"If we have evidence that medical cannabis has the potential to change lives, then we need to do something about it," NSW Premier Mike Baird said.

Mr Abbott said the federal regulator had already approved medicinal marijuana for use under certain circumstances.

Asked whether a federal trial would happen, Mr Abbott indicated the need to wait and see what happened with NSW.

"In the end, it is more state law than federal laws that govern this," he told the Seven Network.

Under new guidelines, police will have discretion to not charge terminally-ill cannabis users and their carers.

Mr Baird stressed recreational use of the drug remains illegal.