On Leash - Whitehorse
Wurundjeri Walk in Blackburn is a lovely little on leash walk along the creek. Trees shade most of the walk, so it is also suitable for hotter days - bring a longer leash so your dog can cool off in the water!
Just follow the tracks closest to the creek and escape suburbia for a short time.

Off Leash - One of the Best - Whitehorse
Let your dog run wild with lots of doggy friends in this beautiful park. Safely separated from traffic in most parts, all you have to worry about is how to get your wet and muddy pooch home after he has enjoyed all Gardiners Creek has to offer. 
Even the playground is fenced off for extra peace of mind. In summer, the only problem you might face are well attended BBQs on the weekends. I'm not sure about your dog, but Giro in particular finds the smell of meat on the BBQs quite irresistible, particularly since someone actually fed him a large piece of meat there once! Maybe they thought it would make the dog go away. Needless to say, such an amazing reinforcement has made Giro check out that particular BBQ site very carefully every time we go there. 

For details on how to get there, where to park and other relevant information, please see this map of Gardiners Creek off leash reserve.

Click here for more off leash parks in the City of Whitehorse.