Symonds, who was sent home by the Australian team management before the one-day series against Bangaldesh in August, will definitely start the first test against New Zealand.
Shane Watson or Jason Krejza, who made an impressive Test debut for Australia against India in Nagpur recently, will be 12th man, Fox Sports reported.
Victoria paceman Peter Siddle has been released from the 13-man squad, and the selection decision regarding the final starting berth, between Watson and Krejza, will be made on Thursday morning.
The pitch is well grassed, and home-town opener Matthew Hayden expects it to be spicy but sunshine on Wednesday had hardened the surface.
The more it rains before Thursday morning"s scheduled start it is more likely that Watson will play.
But Australia are also keen to retain Krejza to ensure they maintain their over rate, which was dreadfully slow in the 2-0 series loss in India.
“We"ll wait and see what happens this afternoon and tonight. I believe there"s a fair bit more rain around that"s forecast. We"ll finalise (the team) tomorrow morning," Australia captain Ricky Ponting said.
Ponting, who had two long discussions with chief selector Andrew Hilditch at the Gabba on Wednesday morning, admitted it would be an extremely tough call on either all-rounder Watson or off-spinner Krejza to be made 12th man.