Australia bowler Stuart Clark has backed Michael Clarke and Brett Lee to be fit for Thursday's Test with New Zealand.

The duo have rejoined the Australia squad after returning from India where they battled illness, but inclement weather in Brisbane has hampered preparations for the match.

"I think he's (Lee) in fine from what I can gather, I haven't heard anything untoward, he's ready to go." said Clark. "Michael's good, apparently he lost six kilos (according to media reports), but I'm not sure if that's quite true. He's looking pretty good to me, he'll be ready to go come Thursday."