Almost two-thirds of Australians support the legalisation of cannabis for medicinal purposes, according to a new poll which coincides with a renewed push to relax the laws.

A ReachTel survey of more than 3400 Australians shows that the majority back medicinal marijuana, with support highest among 51 to 65-year-olds.

It comes as NSW Premier Mike Baird indicated on Wednesday that he supported the use of medical marijuana, despite having concerns about its supply and regulation.

Earlier this month Cassie Batten, a pregnant mother from Mernda, was questioned by police after admitting to using cannabis oil to treat her disabled three-year-old, who has epilepsy and suffers from profound seizures.

But it is unlikely that there will be any legislative change in Victorian in the near future, with both the Napthine government and Opposition saying they have no plans to legalise the drug.