Warner's outburst was no surprise. He' been a fuse-lighter most of his test career, which began against New Zealand at the Gabba four years ago.
Quizzed on a column by McCullum in Britain's Daily Mail several weeks ago during Australia's ODI series in England, in which McCullum criticised the actions of Australian skipper Steven Smith over an incident, Warner didn't hold back.
"In my opinion it was something that was quite poor and immature on his behalf to make the comment about Steve," Warner said.
Smith turned down the chance to call back England allrounder Ben Stokes who had blocked a ball thrown towards the stumps with a hand during an ODI at Lord's in September, and was given out obstructing the field. The key point was whether he was taking evasive action for his safety or blocking a ball perhaps heading for his stumps.
McCullum was uncomplimentary about Smith's failure to observe the spirit of cricket. On Monday, Smith said he had no regrets and would take the same action if it arose again.
Yesterday, Warner, at the end of an engaging chat on a range of first-test topics, waded in.
"For one, as an international cricketer, I don't see the need or the right for a current captain to write columns on another series. After the first one I didn't really pay attention to what he was saying.
"His opinion is going to be heard worldwide but you can't be talking about the players the way he did."
Warner then acknowledged McCullum had "done a great job with the Kiwis and he's trying to make them the world's politest team, and well done to him".
"Politest" was a reference to New Zealand's attitude towards the on-field verbal gymnastics on which Australia have tended to pride themselves down the years. New Zealand's approach under McCullum seems to strike a green-and-gold nerve.
Former test wicketkeeper Brad Haddin's complaint that New Zealand were too nice during their group game at last summer's World Cup stuck in his craw and he let rip at New Zealand's batsmen in the final.
Judging from Smith's comments this week, Australia aren't about to go all lovey-dovey over the coming month.
He has already said Australia will play the standard brand of aggressive cricket for which they are well known, trotting out the old line about the players knowing there's a line they can't cross.
A tasty three-match joust seems in prospect, but at least one New Zealand player is relaxed about it.
"It's not really going to faze me," key bowler Trent Boult said yesterday. "In terms of sledging, the Australians are known for it, I guess. But I can't see us wasting too much energy and trying to get caught up in too much of that stuff."
It was hot at the Gabba yesterday, and Warner pointed out there's rarely any breeze in the cauldron. Even the Indians were troubled by it last season, according to both Warner and teammate Mitchell Starc.
"It's 38 deg out there at the moment so we've got other things to waste energy on than trying to spray the Australians," Boult added.
