Ah, legalese.

The bill (GST on low proced imported goods) was introduced to parliament with a proposed introduction date of 1/7/17.

The bill wasn't passed by parliament and was instead referred to a specific senate committee for investigation. On May 7th the committee presented their report, recommending further consultation with stakeholders and a delayed start date. 

Nothing further has been discussed in parliament that I know of. The bill wasn't passed in its original form, which means it's not yet part of Aus legislation.

The page you refer to was last updated 06 Apr 2017 while the bill was being considered by the senate committee.