The ICC had originally set a deadline of Saturday, August 18 but have now moved that back to Friday, August 24 for members to submit their 15-player squads.
The tournament begins in Sri Lanka on September 18 and runs until October 7.
"The International Cricket Council today confirmed, after receiving requests from several of its Members, that it has extended the deadline by six days for the men’s teams to submit its 15-player squads for the ICC World Twenty20 Sri Lanka 2012," the official statement read.
"All participating men’s teams must have its 15-player squads to the ICC no later than Friday 24 August 2012.
"The date for the women’s teams to submit its 15-player squads for the ICC Women’s World Twenty20 Sri Lanka 2012 remains unchanged and must still be submitted to the ICC by Sunday 26 August 2012.
Australia, however, released their personnel list on Thursday and Brad Hogg will become the oldest cricketer to play for Australia at a World Cup.
The 41-year-old spinner, a veteran of seven Tests and 123 one-day internationals, retired from international cricket in 2008 but re-emerged as a Twenty20 specialist in last summer's Big Bash League.
The Western Australian was included in Australia's squad, which is the same as the T20 squad scheduled to play against Pakistan in the UAE in early September, along with Victorian all-rounder Glenn Maxwell and injury prone speedster Pat Cummins.
Head selector John Inverarity said: "The seam bowling has depth with Clint McKay, Pat Cummins, Ben Hilfenhaus and Mitch Starc along with all-rounders Shane Watson and Dan Christian, and to a lesser extent Michael Hussey, who could be useful for an occasional over or two.
"Similarly there is depth in the spin bowling department with Brad Hogg, Xavier Doherty and also all-rounders Glenn Maxwell and David Hussey. You can then add to that the possibility of the wrist spin of Cameron White and David Warner.
"There is a great deal of explosive strike power in the batting line-up that could see Matthew Wade at six, Cameron White at seven and either Dan Christian or Glenn Maxwell at eight.
"There is also a good blend of left and right-handers with David Warner, Michael Hussey and Wade likely to be in the top seven," he said.
Australia's Twenty20 players have three matches against Pakistan in Dubai on September 5, 7 and 10, before they fly to Sri Lanka for some warm-up matches ahead of the World T20, which starts on September 18.
Australia's ICC World Twenty20 squad: G Bailey (captain), S Watson, D Christian, P Cummins, X Doherty, B Hilfenhaus, B Hogg, D Hussey, M Hussey, G Maxwell, C McKay, M Starc, M Wade, D Warner (Thunder), C White.