A Senate Inquiry has revealed the Department of Agriculture and some industry bodies don't keep a consistent record of who is paying the millions of dollars generated every year via research and marketing levies

The inquiry was set up after Liberal Democrat Senator David Leyonhjelm argued that levy payers should be allowed to vote annually on whether to pay levies, and on how much those levies should be.

Mathew Koval, from the department's policy division, confirmed the lack of information when questioned by South Australian Liberal Senator Anne Ruston.

"Do we actually know who all the levy payers are in Australia? We don't know the answer to that," he said.

"We don't have a list of every levy payer in Australia that we can actually send out at this point in time."

Mr Kovel claims the responsibility for consulting with levy-payers belongs to industry services bodies, like Australian Wool Innovation and Australian Pork Limited.

He says the Department of Agriculture meets with those groups every six months to assist them.

"They must provide a consultation plan to us and we must agree to that consultation plan, and that plan must talk about the approaches they are going to do to try to consult with levy payers," he said.

"And we talk about levy-payers rather than prescribed industry bodies.

"Our interest is making sure that the organisations who are spending the money are actually talking to those who actually are paying the money."

But Senator Ruston argues that the lack of records and information, regarding who and where levy payers are, indicates the system is flawed.

"I think one of the early recommendations that is likely to come out of this hearing is that there has to be way more emphasis on identifying who the levy-payers are, because there's a myriad of benefits that come out of that," she said.

"It's not just for the purpose of expending research and development, but from a biosecurity perspective too.

"If you had an outbreak of an invasive species or an incursion and you needed to consult or notify all of the pig farmers in Australia, for example, would we know where they are?"

Senator Ruston points out that Australian Pork Limited has demonstrated it has thorough and current records of who and where its levy-payers are across the country.

"But there are a lot of industry associations that would not have the capacity to identify their growers," she said.