Sydney Short Stop

Hi,

I'm doing BnR in November and I'm flying to Aus from Hong Kong as I'm spending a few days there before my tour. The only flight I could get to Cairns is via Sydney and I have a 5 hour stopover in Sydney before my flight to Cairns.

Although I'll be back in Sydney at the end of the tour 5 hours is a long time to kill in an airport waiting for just a short-hop flight. Would this length of a stopover be long enough to go and do something or see something in Sydney or is the airport very far away? Would I be better off just waiting in the airport for the 5 hours?

Any feedback would be appreciated!!