Former West Coaster and brewer Paddy Sweeney has Speight's in his sights, accusing the company of "poaching" his Good Bastards brand.
Dunedin-based Speight's has started an on-line search for a 'Good Bastard' of the month, giving away a meat tray to the winner.
But Mr Sweeney, who lost more than $1 million last year when his Westport-based West Coast Brewery went into liquidation, has come out swinging.
"Good Bastards don't do this to people when they are down," he said this week, from his home on the Gold Coast.
Mr Sweeney started his Good Bastards club in Hokitika in about 1995 in the spirit of old-fashioned West Coast larrikinism. The group even featured on the 6 o'clock news and 60 Minutes, and still has a worldwide membership.
They came up with Good Bastards Beer, bought a brewery, published seven Good Bastards books, held over a dozen Good Bastards days, had Good Bastards four-wheel bike musters, awards, rugby tournaments and fishing trips.
Mr Sweeney said he still owned the Good Bastards beer trademark, and it was still being made at his former Westport brewery.
He said he had decided to speak up after pressure from other genuine 'Good Bastards,' mainly made up of current and former West Coasters.
Now in Australia earning a living as a keynote speaker, he said he did not have the means to take on the might of Speight's.
However, he had revived his Good Bastards club, and contest, and was setting up new chapters in Wellington, Hamilton, Auckland, the Gold Coast and even Dublin.
"Why not go to the genuine (and legal) Good Bastards website and nominate who you think is a Good Bastard," he said cheekily.
He wants to raise $1m for worthy causes over the next 10 years, with 100 per cent of the profits going to charity, and has already planned motorbike rallies in Auckland and Queensland.
A spokeswoman for Speight's owner Lion Breweries, Judy Walters, said it was "unfortunate" that Mr Sweeney had objected to its use of the term 'Good Bastard'.
"We do not believe that we are acting in breach of any trademark rules and restrictions," she said.
"Speight's simply adopted this term because of its colloquial use in New Zealand language rather than with any intention to create a 'brand' from it."
'Good Bastard' was a commonplace figure of speech and Speight's doubted that Mr Sweeney, Speight's or anyone else could actually claim it as their own in this context. It was like someone trying to claim ownership of the word 'mate', she said. The Speight's 'Know a Good Bastard?' promotion only featured on the brand's website and was linked to rewarding a behaviour or a humble deed as part of Speight's wider 'Pride in Knowing What Matters' campaign. People could also nominate the 'perfect woman' as part of the same over-arching activity, she said.