Probably not. The aircraft would have been at the extreme edge of the radar's range, and in an area that is probably not getting scanned terribly often.
Jindalee uses a directable beam to scan the area or interest. It takes hours to do a full sweep of its entire range (bear in mind that with over the horizon radars you have to do a 2D sweep, not the 1D sweep of a standard line of site radar). Generally speaking, the radar tends to be targeted on areas of specific interest, not just randomly sweeping (the sweep pattern depends on current threat profiles). Maybe if Malaysian authorities alerted Australia quickly enough they may have pointed the beam to the right area, but as I understand it the alert didn't start going out until much later.
Disclaimer: ex RAAF radar engineer...
> JUST IN: @WrightUps from above Indian Ocean says US P-8 crew "getting radar hits of significant size;" trying to get visuals on hits.
> Australian maritime authority official calls objects credible and of "reasonable" size; largest object about 24 meters.
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ABC journalist David Wright [[0] is currently on the P8 plane that is searching for the debris.
Here's a tweet [1] from ABC's social media editor who (apparently) must have spoken to him over voice comms:
>.@WrightUps from Navy P-8 search plane: "We are just descending through clouds right now ... about 1,300 miles southwest of Australia."
[0] https://twitter.com/WrightUps
[1] https://twitter.com/MicahGrimes/status/446501269155618816