DPF is required since Euro 5b.

Australia is currently at Euro V for heavy vehicles (since 2011) and Euro 5 for light vehicles (since 2013). So they have adopted it in a stage-wise manner. But but but this regulation is only for vehicle-makers (ref: https://www.fuelsandlubes.com/fli-article/australia-considers-move-to-euro-6-vi/). There is no mention of compliance requirements for fuel-makers as far as I searched on the net, just a small “Diesel fuel in Australia is already of sufficient quality to allow for the implementation of the new standard” without going into details, even though the article goes into nitty-gritty details of petrol cars whether they meet Euro 6b or the latest Euro 6d!

Similarly, in this article https://www.abc.net.au/news/2021-10-14/australia-dumping-ground-for-polluting-cars-euro-6-standards/100535418, it is written “The federal government has agreed to implement better petrol quality standards from 2027, which are required before Euro 6 for light vehicles can be mandated in Australia.” so again the automobile industry is facing the pressure to offer cleaner vehicles before cleaner fuels are made available.

Stringent emissions standards are also being seen as a measure to nudge towards EV shift: https://www.abc.net.au/news/2022-08-19/labor-signals-new-standards-to-boost-electric-vehicle-uptake/101349256.

The story of Aus is similar to the story of Pakistan where automakers (which themselves are a strong lobby and laggard in compliance – and complicit in elite capture at the expense of society) can still be pressurized into emissions compliance but it is the oil refineries sector which is more difficult to deal with. Forcing carmakers to comply is “difficult” but forcing oil refineries to comply is “most difficult”. This issue has been discussed before https://carspiritpk.com/byd-faw-chery-joins-price-war-in-chinese-car-market/#comment-13668, https://carspiritpk.com/two-years-and-still-no-euro-5-cars/#comment-11348 and https://carspiritpk.com/euro-2-in-pakistan-a-decade/#comment-9498 and https://carspiritpk.com/blame-where-the-blame-is-due/#comment-7829.

Further good reading w.r.t future engine tech and Euro 7: https://www.fuelsandlubes.com/fli-article/gasoline-quality-lags-behind-needs-of-direct-injection-engines/ and https://www.fuelsandlubes.com/fli-article/euro-7-impacts-on-engines-fuels-and-lubricants/.