What about stopping, how soon can you take your foot off in preparation for stopping? 
Also what about at low speed, you feel like your going to tip over, are you allowed to remove your foot from the peg or are you just expected to fall over with the bike. 

This is one of the rules put up for review from the Victorian Motorcycle Council which covers both points you raise.
http://ntc.gov.au/rfcDocuments/VMC%20NTC%20Aust%20road%20rules%20review%20Submission%20Dec%2020112011122114084211642.pdfRule 271 (1), (2) & (3)
Rule 271 (1) and (2) requires that both the rider and passenger have their feet on the appropriate footrests at all times. The discussion document points out that riders conflict with this rule whenever they use their feet to move the bike backwards.
A rider is also in conflict with this rule whenever they are slow manoeuvring their bike or manoeuvring on a low traction surface and keep their feet near or on the ground to aid stability.
Further a rider or passenger conflicts with these rules when they stretch their legs to alleviate an impending (and potentially distracting) cramp, loosen a clothing restriction or momentarily stretch a weary leg. In the case of a passenger stretching a leg, the rider is required by subrule (3) to stop immediately and is subject to a potential penalty if they don’t, despite a rapid stop being a potentially dangerous manoeuvre.
To
To better meet pragmatic requirements, the following amendments are suggested:
(1) A rider, while riding a moving motor bike, or astride or mounted on a stationary motor bike that is not parked or not in the process of being parked, and who is not a rider walking beside and pushing a motor bike, must:
(a) sit astride the rider’s seat facing forwards; and
(b) ride with at least 1 hand on the handlebars; and
(c) if the motor bike is moving — keep both feet on the footrests designed for use by the rider of the motor bike, unless the rider is managing the motor bike's stability, or one leg at a time is momentarily moved for the purposes of stretching or adjustment.