UPDATE: RACV Senior Vehicle Engineer Nicholas Platt said prices are entirely influenced by local levels of competition.
"The South West Region has one of the most expensive (Ararat) and the cheapest (Portland) fuel in Victoria," he said.
"However, this is not a new phenomenon, with Ararat and Portland have drastically different pricing cycles dating back many years.
"Ararat prices seldom vary drastically from day to day, no matter what the underlining wholesale price is doing.
"Portland on the other hand has a tendency to follow wholesale prices closely and reacts quickly to changes both up and down and has continued that trend.
"Stawell follows a similar trend to Ararat, while Horsham has in the past alternated between a fairly static price and following the wholesale with a reasonably large margin.
"Currently though Horsham prices have been falling quite rapidly with the wholesale prices.
"Melbourne prices indirectly follow the wholesale price as a trend, with daily prices typically following a price cycle where individual retailers undercut each other followed by a peak as they approach wholesale prices.
"While this cycle has been disrupted in recent weeks by the drastic fall in wholesale prices and reduction in vehicle usage, Melbourne prices again seem to be trending down."
EARLIER: Traditionally, the Easter holidays is a time where people would jump in the car and drive long distances to visit family and friends, go camping or just have a break.
This custom has been snapped in 2020, as the COVID-19 pandemic prevents all non-essential travel to curb the spread of the virus.
Deemed an essential service by the government, service stations are seeing customer numbers drop dramatically.
Independent retailer and Haven General Store owner Peter McFarlane said the timing of the shutdown could not have come at a worse time.
"Easter is normally our busiest time of the year," he said.
"We have gone from seeing up to 2000 passing cars on Good Friday in previous years to possibly seeing 20 cars this year.
"No one is moving any fuel at the moment.
"It's out of our control - there's nothing we can do about it."
Mr McFarlane said dropping fuel prices, which have gone from an average of 146.9cents per litre to 121c/l in Horsham, won't make a huge difference.
"It doesn't matter how much fuel costs because people aren't driving around.
"Fuel sales have dropped about 50 per cent.
"Farmers are loving it because diesel is very cheap at the moment and they're still working every day."
As of midday Wednesday, unleaded the majority of Horsham outlets sold petrol at 119.9c/l, with the Haven General Store the lowest with 119.4c/l.
The drop in petrol prices is also linked to a dramatic drop in crude oil prices as Russia and Saudi Arabia engage in a price war.
Wholesale crude oil prices have plummeted in 2020, from US$70 a barrel in January to US$33.
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