question about one way tickets to China

I contacted the Australian Embassy and they told me that Chinese nationals do not need to hold a return ticket to enter Australia. My girlfriend flew from Hong Kong to Brisbane on a oneway ticket with no problems so this is true. We both flew back to PRC before her Visa ran out and I flew back to Australia on a return ticket. Does PRC have a similar agreement with Australia? I would like to book a budget oneway ticket and purchase return ticket in Shenzhen as I am not sure when I would be required back in Australia for work.