An employment lawyer believes a change to whether cannabis is legalised or not will have little affect on how workers turn up to their jobs.

Employment lawyer Blair Scotland told Heather du Plessis-Allan people's mindsets may need to change if the drug is legalised for recreational use.

"They need to move away from this concept being illegal, they need to think more in legal drugs around alcohol. It's still not acceptable to for me stop how up to my work drunk, probably still not going to be acceptable for me to show up to my work totally stoned that I can't function."

Mr Scotland says there is not a scientifically accepted way to test for someone who is impaired at this stage. 

He adds given alcohol's at times acceptance in the workplace, the same could happen with cannabis.

"You could [go out for a 'smoke' break], maybe you go out for a puff who knows.

"Context is going to be everything."