An illegal tobacco crop worth more than $11 million has been discovered during a search by police and tax office officials of a property just south of the ACT border.

As many as 92,000 tobacco plants and two tonnes of tobacco leaves, along with $15,000 in cash, a shotgun and ammunition, were discovered during the joint operation yesterday morning, after a tip of from a member of the public.

The farm was located on Callemondah Road, Shannons Flat in NSW, near the ACT border.

The estimated excisable value of the tobacco seized was more than $11.77 million.

Australian Tax Office (ATO) Assistant Commissioner Peter Vujanic told ABC South East NSW the raid followed a similar one in Victoria earlier this week and was the culmination of a concerted effort to crack-down on illegal tobacco growers.

He said the plants and the leaves have since been destroyed.

Tobacco black market 'quite substantial'

Illegal tobacco leaf found at the Shannons Flat property. ( Supplied: NSW police )

It is illegal to grow tobacco in Australia, with no licensed tobacco producers growing the crop since 2006.

But Mr Vujanic said the black market for illegal tobacco in Australia was "quite substantial".

"There is real appetite through the community with the current [high] cost of legal cigarettes," he said.

Mr Vujanic said illicit tobacco grown in Australia was the ATO's responsibility.

"It's actually an offence under the Excise Act, of which we prosecute offenders, with the Commonwealth Director of Public Prosecutions," he said.