The Greens have been accused of spreading lies and trying to destroy the kangaroo meat industry while meeting with European politicians.
Federal Agriculture Minister David Littleproud slammed Senator Lee Rhiannon over her visit to Brussels, where she is promoting a controversial documentary that questions the extent of kangaroo culling in Australia.
The EU is a key market for the $175 million industry as the biggest importer of premium cuts.
But the Greens senator and the filmmaker behind Kangaroo: A Love-Hate Story say the practices involved in harvesting 1.6 million wild roos annually need to be exposed.
Senator Rhiannon is leading a three-person delegation that's due to meet with European Parliament members on Tuesday about what they argue are the "major risks" to the marsupial's future.
She says population and growth rates are inflated and that millions of undocumented dependent joeys are killed every decade.
Government regulation advises the young of culled animals be euthanised with a blunt object as soon as possible.
"We will use the evidence to show that kangaroos are in trouble," Senator Rhiannon said.
Mr McIntyre, who self-funded the film with Kate McIntyre Clere, says in undertaking a wider examination of the cultural icon, he was shocked to discover the methods used to kill the animals.
He says he isn't out to destroy the industry.
"But do we really want to be bashing joeys' heads against tow bars?" he said.
The senator, who funded her own trip, and the filmmaker were separately invited to the Brussels premiere hosted by Dutch political party Party for the Animals.
The agriculture minister accused Senator Rhiannon of spreading false information in a significant export market.
"It's absolutely disgusting that she would go over there and try and destroy the kangaroo industry that has huge potential for jobs in regional Australia," Mr Littleproud told reporters on Tuesday.
About five million roos were harvested in the three years to 2015 from a population of about 45 million, according to government data.
ANU zoologist George Wilson says animal activists' arguments against factory farming can be supported by some evidence but likened those against roo harvesting to a "noisy minority" in the climate change debate.
"In this case, all they have is their ideology running a line that really does not bear any scientific scrutiny," Dr Wilson said.
The film, which screened in the US ahead of Australia Day, is due to have its Australian premiere in Sydney on March 13.
