The 37-year-old twins were dropped from the one-day squad earlier this year, and the selectors are likely to show the same ruthless streak with the Test side, if necessary.

Both Waughs are keen to prolong their international careers, with the twin targets of playing in this winter's Ashes series and regaining their one-day places in time for the 2003 World Cup.

Border, a former Australian captain, believes both will know when the time is right to walk away.

But he said: "I suppose it is a risk they take that they will have the decisions taken out of their hands.

"If you just keep putting yourself up for selection there will not be a problem as long as your form holds. But the time will come, won't it, it happens to all of us.

"You don't want to pick on emotions too much, but sometimes in the cold, hard light of day you have to make some tough decisions."

Steve is still Australia's Test captain and is expected to lead the side in the series against Pakistan in October, provided it goes ahead as scheduled.

He has scored 9,600 Test runs at an average of 50, while Mark's record of 7,949 runs at an average of 42.28 is also impressive.

"We have a big Ashes series coming up and the experience Stephen brings would be very important. But everyone is under pressure for their position," Border added.