PRICE differences in petrol stations across the country can cost motorists up to £350 a year according to the Automobile Association.

The association has found that petrol prices in the Republic still vary by up to 8p per litre in some areas or 36p per gallon.

The association has also warned that legislation which will require filling stations to observe explicit instructions regarding the display of fuel prices must be strictly enforced.

The legislation was proposed by the Minister for Enterprise and Employment, Mr Bruton, earlier this week. He is expected to announce specific details concerning the new regulations within the next two weeks. Petrol stations will be given explicit instructions on the size, type and exact location of where prices must be displayed.

The forthcoming regulations were announced by Mr Bruton when it was revealed that Statoil would be allowed to proceed with its takeover of the Jet network of filling stations. Under the deal, Irish operator Maxol, will be allowed purchase several Statoil stations and a number of Jet stations.

Initially Statoil wanted to buy all the Jet stations, but this plan was rejected by the Competition Authority which feared a lowcost operator would be removed from the market.

Petrol stations operators are currently bound by an order directing them to display prices prominently. But Mr Bruton told The Irish Times that many stations are offering 20p off without specifying whether it is off a gallon of petrol or a litre.

The new order will specify that petrol price signs must be at right angles to the garage and clearly visible from the road.

Mr Bruton says that special offers on petrol will have to conform to current consumer legislation - if being reduced, the petrol will have to have been sold at the market price for a month beforehand.

Conor Faughnan, of the Automobile Association, whose organisation monitors prices at 60 key petrol stations in the Republic each month, says motorists should ignore special offers.

He says the AA advises motorists to be guided by price alone. He says many garages provide a range of services, but it can add a considerable amount to the petrol price.

The AA has found that competition among petrol retailers tends to be localised. About 18 months ago, Waterford sold the cheapest petrol in the country, at present this honour goes to Dundalk.

Mr Faughnan says motorists who use their cars for business can end up paying around £320 per annum more than they need to and those using cars for family reasons could be paying anything from £120 a year, by not shopping around.

The AA rule of thumb for average petrol prices is: standard unleaded: 56.80p; super unleaded: 62.81p; ordinary leaded: 64.33p and diesel: 55.69p.

As the accompanying table shows prices for premium unleaded petrol in Dublin can range from 54.8p to 61.5p per litre (a difference of almost 7p). Leaded petrol ranges from 62.1p to 65.9p per litre (a difference of almost 3p).

There are marked differences in garages outside Dublin also. In Kilkenny, for example, premium unleaded petrol prices can vary by more than 7p per litre while premium leaded petrol varies in price by 2.5p per litre.

A random survey of 30 garages carried out by The Irish Times in Dublin, Meath, Kildare, Westmeath and Galway, found large variations in price.

In one area in north Dublin prices were remarkably similar, perhaps bearing out the competition theory. For unleaded petrol, prices varied from 59.9p per litre (Maxol) to 62.8p per litre (Texaco). Jet was the cheapest for unleaded petrol in this area, retailing the product at 57.4p per litre.

In South Dublin, a Shell garage was selling unleaded petrol at 55.3p per litre; and ordinary leaded at 63.6p per litre.

Overall, petrol prices outside Dublin were more expensive. In Galway city, for example, prices varied from 54.9p per litre for unleaded petrol (Statoil and Shell) to 61.7p per gallon (Texaco). Super (leaded) varied from 65.7p (Texaco) to 62.9p per litre (Statoil).

In Loughrea, Co Galway, prices were slightly more expensive for unleaded petrol. It cost 59.9p in one Statoil station and 60.9p in a nearby Shell station. Jet came in slightly cheaper than all other operators for unleaded petrol. In Craughwell, half-way between Loughrea and Galway, a Jet station was selling unleaded petrol for 59.5p per litre. It was selling leaded petrol for 63.5p, just over a halfpenny dearer than Statoil in Galway city.