Looks like an Eastern Water Dragon to me. From wildlife.qld.com.au:
Sexually dimorphic with males more robust than females. Prominent spines on head and along length of back, with a laterally compressed body and tail. Long powerful limbs. Olive green to brown in colour with short dark bands on the body, dark stripe behind the eye. Males have a distinctive red flush over the chest.
From http://reptilesofaustralia.com/lizards/agamids/plesuerii.htm:
Apparently they make good pets, but like all goannas, lizards, dragons, crocodiles etc., the bite could be nasty and depending on what they have in their jaws, could be easily infected.
Credit:stackoverflow.com‘