Drivers have been advised to sniff out "unexplained strong tobacco odours" and locals told to look for earthworks along creeks and rivers on private and public land.

Other telltale signs are said to include suspicious responses to real estate ads and farmers trying to lease land outside their home states.

Home Affairs Minister Karen Andrews wants amateur sleuths to blow the whistle.

"Anyone who sees something that they think is suspicious, please dob them in," she told ABC radio on Thursday.

Tobacco is traditionally grown in tropical climates like north Queensland but illegal plantations have cropped up in Victoria and NSW, triggering a series of recent raids by state and federal police.

The minister acknowledged cigarettes were incredibly expensive in Australia but argued that was no excuse for illegal activity.

Ms Andrews also raised concerns about illegal cigarettes coming into Australia from overseas.

"It's often used as a way to test trade routes and to test the measures that are in place to detect illegal activity in Australia so that the criminals can start importing drugs," she said.

"So there's a couple of sides to the activity with illegal tobacco - the illegal tobacco itself, and also the fact that it's used effectively as a precursor to bringing drugs into the country."

The federal government pockets 40 per cent of the price of cigarettes and claims the illegal trade cost $1.7 billion in lost excise last year.

"That could go towards roads, hospitals, buying vaccines," Ms Andrews said.

"So the taxpayer is, in effect, missing out of a lot of that revenue."

Australian Associated Press