A motorist has been snapped filling up large plastic containers with cheap fuel as drivers start to panic buy ahead of tonight’s reinstatement of the tax discount.

Traffic queues are spilling on to streets outside Auckland’s cheapest service station at Westgate’s Costco, where 91-grade fuel costs $2.14 a litre.

At midnight the fuel will cost 29c a litre more when the tax discount ends.

A motorist was seen stockpiling fuel ahead of tonight's price hike. Photo / Supplied

Last night a motorist keen to beat the looming price hike packed six large containers in the back of his hatchback and proceeded to fill them up.

“Bro came prepared” posted a passing motorist on Facebook who spotted the man at the station.

Cars clog up streets around Westgate this morning as motorists rush to get cheap petrol. Photo / Michael Craig

Today streets surrounding the country’s only Costco were clogged for the second day running.

Yesterday the large self-service station, which can only be used by customers with membership, had up to 40 vehicles waiting in line to fill up.

The line now stretches around neighbouring roads and threatens to block the nearby Northwestern Motorway off-ramp.

Traffic has become so bad Auckland Transport this afternoon diverted a number of bus routes away from the congestion and advised passengers there would be six stops missed.

Yesterday Simon Bradwell of the Motor Trade Association urged motorists facing queues at gas stations to be kind to staff.

The Automobile Association’s Terry Collins said the upcoming price increases would not be as severe as a year ago when prices reached an all-time high, surpassing $3 per litre for 91.

“Few people will be happy about fuel prices going up, but international oil prices aren’t currently at the highs they were when the tax discount was introduced so the impact will be lower,” he said.

Long queues have formed for Costco petrol ahead of tonight's reinstatement of the tax discount. Photo / Michael Craig

A government spokesperson said the temporary removal of fuel excise was designed to support New Zealanders through the global energy crisis last year, which saw petrol prices spike above $3 a litre.

“Petrol prices are now 70 cents per litre lower than they were in early March last year when fuel excise was removed.

“Other countries that also removed fuel excise at that time like Australia, Ireland, and Germany have already reinstated their fuel taxes as the global price of fuel has eased.”

The spokesperson said the petrol excise cut was always temporary, but was extended a number of times and has seen over $1.4 billion invested to support households through the global spike in petrol prices.

Collins said the tax relief was welcomed by the AA but it accepted it had to be added back at some stage - with motorists using the roads coughing up rather than all taxpayers.