The Maheno on Fraser Island is slowly rusting away and a tour guide told us it is predicted that it will be gone within the decade. There were warning signs to stay at least 3 metres from the structure which almost everybody ignored and there were a lot of people. There is always a risk that the rusty parts could give way and fall on someone.
I've filmed at the Tangalooma wrecks on Moreton Island off the Brisbane coast. It's a magical site (and relatively safe) to snorkel and swim around. The wrecks are close to the main beach and the water is always clear and a magnificent blue colour with an abundance of marine life. It's truly spectacular.
As it's within the confines of being part of a National Park, the Government has done a superb job in clearing out most of the obstructions making this a very safe area to dive, snorkel and swim in.
Yes, I had a look at/climbed on the wreck of the Cherry Venture on the Sunshine Coast when I was a kid, and yes it is definitely dangerous being full of bits of sharp rusty metal and unstable parts that could collapse at any time. You certainly shouldn't actually climb on the ship as we did (kids do crazy stuff sometimes).