‘That's the umpires' job to tell us when we're getting close and that's what happened today’
Both Australia and New Zealand played down any significance of the umpires warning the visitors for throwing the ball to wicketkeeper Peter Nevill on the bounce in order to aid its deterioration during the third day of the second Test on Monday.
The visitors are on the brink of a comprehensive victory over New Zealand at Hagley Oval after the hosts ended the day on 121 for four, still 14 runs away from making Australia bat again.
Steve Smith's side were dismissed after lunch for 505 and a first innings lead of 135 runs.
Australia's Josh Hazlewood and James Pattinson then extracted conventional and reverse swing, particularly during the final session when heavy cloud, blustery winds and cooling temperatures aided their efforts.
Australia however were also warned after the 20th over for throwing the ball into Nevill on the bounce in order to further scuff up one side of the ball, though both Adam Voges and New Zealand wicketkeeper BJ Watling said that was part of the game.
"There is a line and I'm sure that most fielding teams will get as close to the line as they can without overstepping it," Voges said. "That's the umpires' job to tell us when we're getting close and that's what happened today.
"We kept it up pretty well after that."
Watling said the New Zealand side had no qualms about the Australians' tactics of trying to rough up the ball, even though their bowlers had been unable to extract any appreciable swing or seam movement throughout the series.
"That's just part of the game to be honest. You throw the ball in from the boundary and it bounces. That's just cricket," Watling said, while adding they had spoken about possibly attempting to do the same when they bowled.
"We do talk about that. You try to get it to go if you're not getting much swing. They were successful at it and we didn't quite get it to go."
Voges said he felt the Australians' superior pace was also helping them move the ball more, while the hosts have had to do much of their bowling in brilliant sunshine and with pitch conditions favouring the batsmen.
"I don't know if we were doing anything differently but maybe with a tad more air speed that maybe exaggerates reverse swing a little bit more," he added.
"We got one of the sides a little bit scuffed and looked after the other side and away we went."