SYDNEY  - David Warner and Ed Cowan must contemplate leading Australia after Michael Hussey's retirement added further to the leadership conundrum created by Michael Clarke's tender hamstring and Shane Watson's uncertain international future. The loss of Hussey and Ponting in the space of three Test matches means Australia are not only without two of their most seasoned batsmen but also the likely candidates to lead the Test team in the event of Clarke and Watson being unavailable.

Watson has already been ruled out of the New Year's Test in Sydney due to a calf problem that may well sound the final knell for his attempts to maintain fitness as a Test match allrounder, and Clarke is again in some doubt with a strained hamstring. Hussey's decision to retire shocked Clarke and Australia's coach Mickey Arthur, leaving them short not only of their most complete batsman but also a safe candidate for short-term leadership duty.

Arthur had been digesting Watson's confession that he may no longer be an allrounder in the future in the hours following the Boxing Day Test when he felt a tap on the shoulder. Hussey requested an audience with Arthur and Clarke, whereupon the 37-year-old confirmed his intention to retire at summer's end. The instant response of Clarke and Arthur was to leave Hussey room to reconsider.

"We'd done our selection meetings, we'd got everything out of the way, and Watto and I had a chat to see where he was with his injury and Watto hinted that he might just consider being used as a batsman from now on, so that was a little bit of a shock," Arthur told ESPNcricinfo. "And then I thought I'd just have a beer now and enjoy the win and Mike Hussey tapped me on the shoulder.

"So my first reaction was 'wow', it was myself and Michael Clarke and Huss together, Clarkey and I looked at each other and it was just 'wow, what do we do'. We congratulated him on a fantastic career and said 'are you sure?' but Huss had made his mind up and like a true champion he's done it very well."

Warner and Cowan have both been mentioned as potential captains, after leading various teams in the past 12 months. Warner led the Sydney Thunder and a CA Chairman's XI last summer, while Cowan guided Australia A on their winter tour of England and showed his batting could benefit from the extra responsibility by comfortably topping the tour aggregates.

Australia's plans for the tours of India and England in 2013 had been drawn up with Hussey as a central part, especially after Ponting's loss of form had hastened his exit from the national team. Arthur said a swift change of tack was now required, and he placed onus on the likes of Warner, Cowan and Watson when he returned to fitness to step into the breach.

"We were certainly building a top six around that," Arthur said. "We always knew Clarke was there, and once Ponting went we knew we had Hussey. We had all our plans in place, so with no warning it was a shock, but I totally understand his reasoning and respect his decision. He deserves to go out the way he is. But for us now it's about moulding a top six that's going to win us a Test series in India and win us an Ashes - an enormous task.

"In our Test team you've got to hope that David Warner and Shane Watson really step up now. I'm pretty confident they'll do that. In Ed Cowan you've got a very wise head, a very good, calming leader around the group. So they need to stand up. I said to the group when Ricky left I wanted everyone to stand up and give us 5% more, now we're going to have to ask everyone to stand up and give 15% more, because we need to fill that void now that we've lost, and we need to fill it very quickly."

That void was painfully evident on last year's ODI tour of England, when a team minus Ponting and Hussey - who missed the trip for family reasons - was battered 4-0. Arthur said that while excesses of rain and inadequate preparation factored into that result, he acknowledged the team dynamic was changing enormously without the guidance and example offered by Hussey.

"We were outplayed in that one-day series, but there were so many mitigating factors," Arthur said. "We couldn't train with rain, we'd come basically out of an off-season, whereas now we wouldn't have, our planning is in place and is spot on in terms of giving guys enough cricket and preparation leading into that first Ashes Test match. That won't be a problem, but what we are looking for is some guys to really stand up and take the opportunity because there are opportunities out there for somebody to make it his own.

"The team dynamic's definitely changed a massive amount when you consider you've lost Ponting and Hussey in a couple of Test matches. Mike Hussey's a phenomenal player and I was gutted when he told me because he's been such a reliable batsman. But you've got to look to the future, you've got to look to who's going to step up. We've got so many options available and I'm so excited to see who steps up and who takes on what is a really demanding year for us."