Hard-pressed motorists have seen the cost of filling up their cars with fuel soar by more than 25% since the start of the year – but can still make significant savings by shopping around.

A Sunday Tribune survey of 10 service stations in the Dublin city area last week found that prices can vary by as much as 5c per litre of petrol, and 6c per litre for diesel.

Frequently, garages offering lower prices were located less than a five-minute drive from their more expensive competitors, with some Dublin motorists asked to pay as much as 121.9 cent for a litre of petrol, and 108.9 cent for a litre of diesel.

Overall, there has been a major increase in the cost of motoring here since fuel prices hit a low in January, an analysis of AA Ireland's monthly surveys over the past year reveals.

This has prompted the AA to claim that motorists are losing out, as prices have fallen elsewhere in the economy.

Last January, the average price of a litre of petrol nationally stood at just 94.6 cent per litre, compared to 94.4 cent for a litre of diesel.

But by April of this year, the average cost of petrol was 106.4 per litre, compared to 99.9 per litre for diesel, an upward trend which has since continued.

By June of this year, the average price nationally stood at 116 cent for a litre of unleaded petrol and 104 cent for a litre of diesel.

However, a snapshot Sunday Tribune survey undertaken in the middle of last week reveals that some Dublin filling stations are charging 121.9 cent for a litre of petrol, and 108.9 cent for a litre of diesel.

Both of these prices were on display in neighbouring Topaz and Texaco garages on the Howth Road in Raheny last week, and represent an increase of over 25% on the average national price last January.

They also compare unfavourably with prices at stations located just a short drive away on the Malahide Road.

For example, a Topaz service station next to the Clarehall shopping centre was last week selling unleaded petrol for 118.9 cent per litre, and diesel for 104.9 cent per litre.

Less than 200 metres away from this station, Tesco in Clarehall was offering the cheapest petrol and diesel in our survey, undercutting its rival by two cent per litre for both petrol and diesel.

Conor Faughnan, public-affairs manager with AA Ireland, noted that between 60% and 65% of the retail cost of petrol and diesel here is made up of government tax.

While this compares relatively favourably with other EU countries, he said a reduction in taxes – tariffs on both diesel and petrol have been increased in recent budgets –would help consumers and businesses.

He said that, nationally, most garages do not appear to be putting up prices faster than they are lowering them when international oil prices change, but said this was "not to say you don't find individual localised instances".

Changes in the price of a barrel of oil typically take two to four weeks to filter through to the forecourt, he added, with the length of time it takes individual garages to go through their existing stock of oil another factor.

"Motorists really should shop around for rather than staying loyal to one or two garages out of habit," he said.

How forecourt prices in Dublin compare

Topaz, Kilmainham: Unleaded 119.9; Diesel 105.9
Maxol, Dolphin's Barn: Unleaded 120.9; Diesel 106.9
Maxol, Harold's Cross: Unleaded 118.9; Diesel 103.9
Esso, Rathmines: Unleaded 119.9; Diesel 105.9
Topaz, Usher's Quay: Unleaded 119.9; Diesel 104.9
Texaco, Howth Road: Unleaded 121.9; Diesel 108.9
Topaz, Howth Road: Unleaded 121.9; Dieseel 108.9
Tesco, Clarehall centre, Malahide Road: Unleaded 116.9; Diesel 102.9
Topaz, Malahide Road: Unleaded 118.9; Diesel 104.9
Esso, Ballybough Road: Unleaded 119.9; Diesel 106.9