Pauline Hanson has raised concerns about bank staff rustling cattle when they repossess farms.
During a Senate committee hearing on Wednesday, the One Nation leader quizzed agriculture department staff about what happens when receivers or bank managers impound cattle on repossessed properties.
"These cattle are not always (owned by) the graziers or the farmers, they can be agisted on these properties," Senator Hanson said.
"It has been actually reported that tags are then removed from these cattle and replaced with fresh tags."
That was equivalent to cattle rustling, a department official said.
"Obviously tampering with the tag on any animal interferes with its traceability and it is an offence and in the circumstances you're referring to is an offence under state law," Assistant Agriculture Minister Anne Ruston told Senator Hanson.
She said she would be happy to pass any information from Senator Hanson to Agriculture Minister Barnaby Joyce but recommended the Queensland senator also tell police.
"I think it's been brought to the attention on many occasions of the police and nothing's been done about it," Senator Hanson said.
Committee chair Barry O'Sullivan, a fellow Queenslander, said he had received the same briefings and encouraged Senator Hanson to pursue it - but said she should be asking law enforcement not the agriculture bureaucrats.
Labor senator Glenn Sterle urged Senator Hanson to name names under parliamentary privilege.
"If the senator does have evidence, put the names on the table, dob them in," he said.
"It's not the first time this committee has had heartburn over accusations of cattle rustling and swapping tags but no one's come up with names or proof, which is the frustrating thing."
Senator O'Sullivan said there were names and proof this time.
However, he moved the committee onto other questions before Senator Hanson could indicate whether she wanted to reveal them.