Petrol prices are set to jump after the national fuel tax discount ends at midnight.

The full effect of the ending fuel excise cut is likely to take months to be felt, hitting supermarkets as well as the bowser, but the watchdog will be keeping an eye out for retailers pushing prices up promptly after the rate rises on Monday.

WATCH THE VIDEO ABOVE: Motorists urged to fill up before fuel excise cut ends at midnight.

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Wholesale petrol and diesel prices will rise by about 16c per litre, with a scheduled inflation-linked adjustment to add roughly one more cent, taking the overall increase to about 17 cents litre.

Unleaded petrol at the bowser expected to soar to above $2 per litre.

This is the final stage of the federal government’s temporary subsidy on the fuel tax, introduced in April to provide relief for motorists amid the war in the Middle East and the impact it was having on oil in the Strait of Hormuz.

Motorists are urged to fill up before midnight, but only with what is needed, to avoid panic buying.

Not immediate, but definite

No capital city will escape the rise, with average unleaded prices forecast to climb beyond $2 a litre across the country, according to NRMA spokesperson Peter Khoury.

Diesel is expected to reach between $2.30 and $2.40 a litre, placing further pressure on households already struggling with rising living costs.

“You won’t see it immediately at the bowser. It will take time for those increases to pass across the country, but increase they will,” Khoury told Sunrise on Saturday.

The 16-cent-a-litre discount had been retained for an additional month after the government wound back its initial emergency fuel excise cut in July.

The temporary relief will now disappear entirely as the excise returns to its full rate from Monday.

Khoury said fuel prices are currently well below the extraordinary peaks recorded at the beginning of the war in the Middle East, when unleaded petrol reached about $2.60 a litre and diesel climbed close to $3.30.

A recent easing in global oil prices, from more than $142 a barrel to about $133, could also help cushion some of the coming increase.

Despite that, Australians can expect the pain to build throughout next week as service stations progressively replace their existing supplies with fuel purchased at the higher wholesale price.

Unleaded averages for capital cities

These are the current unleaded averages for capital cities.

Adelaide: 196.0 cents per litre

Brisbane: 196.3 cents per litre

Canberra: 203.6 cents per litre

Darwin: 207.3 cents per litre

Hobart: 201.2 cents per litre

Melbourne: 196.1 cents per litre

Perth: 192.1 cents per litre

Sydney: 193.5 cents per litre

Drivers warned against panic buying

Khoury urged Australians not to rush to service stations or stockpile fuel before the discount ends, warning panic buying could push demand, and prices, even higher.

“Fill up when you need it. Let’s not change our behaviour,” he said.

Instead, drivers have been encouraged to compare prices before filling up, with significant differences often found between service stations in the same suburb.

Motorists can use the NRMA app and state government fuel-price platforms to check real-time prices and identify cheaper stations nearby.

Supermarket pain to come

It is only a matter of time before supermarkets begin to pass on their own increased costs to customers.

AMP Chief Economist Dr Shane Oliver said the price increases would take a few months to flow through to supermarkets.

“It takes a while for the prices to go up. They won’t go up instantaneously, as we saw with the first halving of the fuel tax cut earlier in July,” he said.

“It will show up in the next couple of months.”

The economist warned the impact extends beyond just the tax change, with rising oil prices due to the escalating war in the Middle East adding to costs for plastics, fertilisers and airfares.

“It’s quite easy, if world oil prices keep rising like they have, that we could be back at $3 a litre for diesel, unfortunately.”

When asked about becoming more self-sufficient, Dr Oliver said the long-term solution involves becoming less dependent on fossil fuels, through electrification, with short-term solutions involving becoming less dependent on the Middle East for oil.