Upper House MP Ivan Dean says support is snowballing for his bid to raise the state's smoking age to 21.
The latest YouGov poll found support has risen to 78 per cent, or around four out of every five people, for the measure.
The Hodgman Government maintains it has no plans to change the age from 18.
The Windermere MLC says he's still putting the finishing touches to the legislation to be debated in coming months.
"One of the amendments that we're currently putting in place is this bill will commence on a certain date," he said.
"Retailers will only ever have to consider one date of birth...a person born on or after 1 July 2002 won't be able to be sold tobacco products."
The bill, to be rolled out over three years, would target retailers rather than young people caught lighting up.
"The first year, it will be those turning 18 years, the second year it will be those turning 19 and the third year, those turning 20 years."