But figures show large discrepancies between service stations with some motorists missing out on the savings.
At least 127 petrol stations, mostly in regional parts of the state, have not changed their prices yet.
In some cases, prices have actually gone up.
“It’s really important as consumers that we reward the stations that are doing the right thing and that we drive straight past the ones that are doing the wrong thing, maybe even report them to the ACCC,” Joel Gibson from One Big Switch said.
The biggest price savings were at the 7-Eleven at Green Valley where petrol dropped by 52 cents, and the 7-Eleven at Sutherland and Coles Express Gymea dropped by 45 cents.
Meanwhile, the Ampol Foodary in Marsden Park decreased by 44 cents and the BP and Caltex Woolworths in Bonnyrigg fell by 43 cents.
The cheapest petrol as of midday was the Metro Guildford where E10 sat at $1.52 a litre.