The Automobile Association is urging other petrol retailers to follow Gull's lead and drop the price of petrol before people head home at the end of the long weekend.
Gull has cut its petrol prices by 10 cents a a litre from Monday until Tuesday morning.
The association's petrol watch spokesperson says all fuel companies can afford to drop prices further, and on a permanent basis.
Mark Stockdale says the wholesale petrol price has fallen by 6c per litre in the past month, but most retailers have only dropped their prices by 4c.
Mr Stockdale expects any fall in the price at competing petrol stations to be confined to those near Gull stations.