Transit visa for Australian Passport holders at Bejing to join a cruise going to Singapore

We (myself and my wife) hold Australian Passports. We plan to a take a Cruise from Bejing on the 8 April 2016. This cruise ends in Singapore. We shall be travelling by air to Bejing airport with one-way tickets and hold Cruise tickets from Bejing.
Can we get 72 hour transit free stay at Bejing before joining the cruise? Thanks for your help.