144 hours days pass

It's impossible to cross the border overland and to enjoy 144 hours visa free transit in Guangdong province. The only solution is to cross the border and apply for 3 day Zhuhai VOA. Anyway, here we have another problem... Australian passport is eligible for the mentioned VOA and Malaysian only if it has been granted a Chinese visa previously. Also, Malaysian citizens are not eligible for 72/144 hours visa free transit at all.

Here just one more possibility, but only for Australian passport holder. You can take a ferry or bus to Hong Kong airport and from there take a flight to Guangzhou with intention of making a return to Macau. This would make you eligible for 144 hours visa free transit. After that, you can stay in entire Guangdong province, including Zhuhai, but you will have to return to Macau by ferry from Shekou Shenzhen port. The reason for that is that actually this is the only option where you can book in advance, online your ticket from Guangdong province to Macau. In short, it's possible, but also a bit complicated.

At least, now you know your options...