Petrol prices have plunged across Australia as the coronavirus pandemic has brought travel to a standstill.

Adelaide has the cheapest fuel in the country on average with prices falling to 89.5 cents per litre on April 1 for unleaded.

Prices have climbed since then, however, reaching 97.12 on average on April 15.

Some service stations, however, are offering well below the average price, with one person posting to Reddit a price of 64.9 cents per litre they found in the inner northern Adelaide suburb of Greenacres on Thursday.

One person posted to Reddit a price of 64.9 cents per litre they found in the inner northern Adelaide suburb of Greenacres on Thursday

People commenting on the post said other suburbs around Adelaide had similar prices.

'I thought 74c in Seaford was good. Some guy in front of me wound his window down to tell me to go first because he was going to put 200L in,' one person said.

Brisbane currently has the second cheapest price at the bowser of 98.3 cents per litre on April 15 for unleaded - falling from 112 cents per litre on April 6.

Melbourne prices are some of the most expensive in the country but there is a consistent downward trend.

The average price for unleaded was 120.3 on April 6 and fell to 106.5 on April 15.

In Sydney, fuel prices are also continuing to plunge sitting at 110.4 cents per litre on April 8 and then 101.1 on April 15.

This is the first time in almost four years prices have neared $1 a litre in Sydney and they are expected to fall below 90 cents in the coming days.

Sydney's average price of near 100 cents per litre for regular unleaded is the lowest since August 2016, with more than 57 per cent of the city's petrol stations offering even cheaper fuel.

NRMA spokesman Peter Khoury said the plummeting wholesale price - currently 82.5 cents per litre - meant the average unleaded petrol price would fall below 90 cents per litre in the coming days, hitting 2002 prices.

He said the average price in Sydney has fallen more than 37 cents per litre in the past four weeks.

'The people currently driving on our roads are healthcare workers and first responders, workers delivering essential services and families shopping for groceries - the people who desperately need some relief at the bowser right now,' Mr Khoury said in a statement on Thursday.

Perth, meanwhile, is the only city where petrol prices are continuing to follow strong weekly fluctuations.

The price for unleaded petrol on average on Thursday April 9 was 109.5 cents per litre before falling to 90.8 on Tuesday April 14 and then rising again to 108.9 on Wednesday April 15.

A person filling up their car with fuel at a service station in Sydney, Wednesday, October 2, 2019 with the electronic sign a reminder of how much prices have fallen



