Lining up before you fill up is tedious at the best of times, but can you imagine waiting more than an hour for petrol?

That's what dozens of motorists were prepared to do at a service station in Perth just to get fuel a little cheaper than nearby outlets.

Video from outside a Caltex petrol station in Mirrabooka, in the city's northern suburbs, showed queues at least 15 cars deep for each pair of pumps.

Dozens of cars lined up outside a Caltex petrol station in Perth, at least 15 cars deep for each pair of pumps

The service station was barely visible in the distance with the car park in front of it completely filled and several cars behind it.

At the back of the queue was a fuel truck waiting to deliver more petrol to satisfy the motorists' massive demand.

The queue formed as the Caltex was selling unleaded petrol for $1.087 a litre, the cheapest in Perth's north.

Motorists waited at least an hour to fill up their tanks in Mirrabooka, in the city's northern suburbs

At the back of the queue was a fuel truck waiting to deliver more petrol to satisfy the motorists' massive demand

Other outlets were selling for five to 10 cents more a litre, saving about $8 on a full tank for a full-size family car.

But some social media users questioned whether waiting an hour for petrol was worth the money, especially with the fuel it took to sit in line.

The station is known for offering cheap fuel and is regularly swamped with cars during the cheapest days of the week, but rarely this much.