Ricky Ponting has been fined 40% of his match fee (approx A$5,400) and rebuked by the ICC match referee Ranjan Madugalle after finally cracking under the strain of impending Ashes defeat on the second day in Melbourne. His angry discussions with an ice-cool Aleem Dar, early in the second session, were the day's major flashpoint as he picked a series of arguments with the umpires and Kevin Pietersen after the batsman correctly survived a caught-behind referral.

The umpires reviewed footage at the close of play before filing a report to the ICC, in which Ponting pleaded guilty to a Level 1 offence under article 2.1.3 (h) of the code of conduct, which relates to "arguing or entering into a prolonged discussion with the umpire about his decision. "Ricky's actions as captain of his country were unacceptable," Madugalle said in an ICC statement.

"A captain is expected to set the example and not get involved in a prolonged discussion with the on-field umpires and question their decision. While pleading guilty to the charge, Ricky understood that the discussion went far too long. He apologised for his action and stated that he has nothing but respect for the umpires and his on-field actions were not intended to show disrespect to Aleem Dar or Tony Hill."

Ponting said he didn't intend to be disrespectful. "I entered into discussions with the umpires about the detail of the decision having viewed replays being shown on the big screen," he said in a statement. "I accept the discussion went for too long and I understand the reasons for the dissent charge handed down by the ICC.

"I was simply trying to seek clarification from the umpires regarding how the decision had been made after being referred to the third umpire. However I would be unhappy if anyone thought I was being disrespectful towards the umpires as this wasn't my intention."

Peter Siddle repeatedly refused to comment on the incident when he spoke an hour after stumps while Jonathan Trott, who was batting with Pietersen, insisted he didn't hear anything. Numerous replays and Hotspot graphics showed no inside edge from Pietersen's push off Ryan Harris, but Ponting remained convinced there had been a mistake.

Siddle, who was not bowling at either end, began the animated protest to Dar by pointing at the video screen in the stands, convinced a mark had been made on Hotspot when the ball passed the bat. No highlight existed near the trajectory of the ball and the Snickometer supported the decision of Marais Erasmus, the third official.

The former Australian captain, Ian Chappell described the incident as "ridiculous", but added that the ICC was partly to blame for failing to clamp down on Ponting's past indiscretions. "It's not the first time that Ponting has argued a judgment call with an umpire," Chappell told ESPNcricinfo. "Cricketers aren't silly. If you ping them for doing something wrong, they quickly learn that you don't do that. But if you let them get away with it they think 'oh well, it's obviously alright to keep doing this'."

Ponting is struggling for runs, carrying a fractured finger and seems only a couple of days from becoming the second Australian captain to lose three Test series against England. Until today he had remained calm under searing scrutiny, but he broke for the first time in public as he backed up his bowler.

The pair surrounded Dar in a scene more likely to occur in a soccer game after a disputed foul, although there was no contact with the official. Ponting then took over from Siddle as the lead prosecutor, standing with hands on hips and then pointing and waving his arms in an exchange that lasted for more than a minute. Dar stayed calm and appeared to indicate that the ball had not brushed the bat where the fielders thought there was a mark. That was clear to all those watching on television, but not to the Australians on the field.

Ponting's mostly one-way conversation carried on for so long that the crowd started to boo and Dar eventually ambled off to square leg to get into position for the next over. Pietersen, who was on 49, was then met by Ponting mid-pitch as the captain continued to vent. There was more booing when he stopped for another lengthy debrief with Tony Hill, the other on-field umpire.

Australia's batsmen lost their discipline on the first day when they were dismissed for 98 and today the captain's behaviour slipped. After the over Ponting, a man at the end of his tether and probably close to the end of his reign, sought out Dar again.

Initially the wicketkeeper Brad Haddin was the only one who thought Pietersen had edged behind, with Harris and Shane Watson, the first slip, not remotely interested. Ponting was swayed by Haddin's claim and called for the replay. The decision wasn't costly because of Ponting's smart call to bring on Siddle, who got one to keep low and had Pietersen lbw for 51.

Ponting's day grew worse when he thought his throw from deep midwicket resulted in the run-out of Jonathan Trott, but the replays forced the umpire to rule in favour of the batsman. Before tea Matt Prior was given out caught behind off Mitchell Johnson on 6 and was saved when Dar asked for a replay that showed a no-ball.