Australian captain Michael Clarke remained sidelined from Champions Trophy action after he was ruled out of Wednesday's match against New Zealand, Cricket Australia said in a statement on Tuesday.
A recurrence of the star batsman's longstanding back injury meant he missed defending champions Australia's opening 48-run defeat by England at Edgbaston on Saturday.
He will again be absent when Australia return to the Birmingham venue for their trans-Tasman Group A clash with New Zealand on Wednesday.
Australia are now pondering Clarke's fitness for next week's final pool match against Sri Lanka at the Oval.
By then, however, they may not be in a position to reach the semi-finals should they be defeated by the Black Caps and other results go against them.
In a Cricket Australia statement issued on Tuesday, team physiotherapist Alex Kountouris said: "Michael is continuing to have intensive treatment in London, and whilst he is making good progress, he has not improved sufficiently enough to play the game against New Zealand on Wednesday.
"We will continue to monitor his progress and determine his availability for next week's final group game against Sri Lanka."
In Clarke's absence, Australia were bowled out for just 65 in a warm-up match by India and could only manage a modest 221 for nine against England, raising fresh questions about their top-order batting.
Clarke is considered a key figure, both as captain and batsman, for when Australia begin their bid to reclaim the Ashes from England when the first Test at Nottingham's Trent Bridge ground starts on July 10.