Papadatos, the current Australian Foursomes champion with Kevin Marques and quarter finalist at the 2011 NSW Amateur, recorded opening rounds of 77-67 to be at even-par for the tournament.
McGrory had opened with a 1-under-par, 71, but a second round 2-over-par, 74, in challenging conditions during a weather hampered tournament did damage to his hold on the lead.
McGraw is in a tie with McGrory in 2nd position after rounds of 74-71.
Australian Amateur Stroke Play and Australian Boy's champion, Cameron Smith, struggled a little returning a four-over-par 76 to be six shots off the pace and at 6-over-par after opening with a 74.
With treacherous conditions predicted to continue for the third and fourth rounds, anything is possible to eventuate at these championships.
The cut of 56 players required a 36-hole total of 14-over-par or better.
The leading 16 players of the Stroke Play will proceed through to contest the Queensland Amateur Championship held at Arundel Hills on Tuesday.
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