"There was unanimous agreement that the off-spinner's 'other-one', the doosra, should not be coached in Australia," Mallett wrote in the Adelaide Review. "I have never seen anyone actually bowl the doosra.
"It has to be a chuck. Until such time as the ICC declares that all manner of chucking is legal in the game of cricket I refuse to coach the doosra. All at the spin summit agreed."
Australia's No. 1 spinner Nathan Hauritz has been working on the doosra for a couple of years without perfecting it, while Jason Krejza and Dan Cullen have also attempted to develop the delivery. However, the spin coaches were keen to encourage Australia's young spinners to bowl aggressively, searching for wickets, rather than becoming too defensive.
http://www.cricinfo.com/australia/content/story/416499.html