Upvote:1
You would need a visa to get out of the airport.
Australians can now avail visa on arrival in India but it would cost $60 per person and to make it easier for yourself you can apply for the visa online and also make a payment.
Upvote:3
Yes, visitors (and transit passengers) from nearly all countries require a visa to enter India.
Recently (27 November 2014), India implemented ETA procedures, which allow citizens of over 40 countries including Australia, to apply for a tourist visa online. See the Indian government site Tourist Visa on Arrival for more details and online application forms.