The European Consumer Centre in Dublin says car hire is one of the top areas of complaint it deals with every year. It provides advice on the pitfalls facing many customers.

The main problems arising with car hire tend to be the same ones repeatedly. The car hire business is generally unregulated and sharp practices have developed in some parts of the industry. There are certain key issues that can cause a problem for people renting. And some of them amount to rip-offs.

They include: 1 - Sales agents insisting that customers need extra excess insurance to cover all eventualities. Agents are usually paid a commission on every "extra" they sell, so you can expect a push to take out more insurance. You can deal with any concern you might have by taking out an annual excess insurance policy - it can cost less than €100 and can be used multiple times - it's a valuable option for anyone who rents cars regularly and it's much cheaper that what a hire car agent will offer. It's even worth a once-off purchase and it will probably pay for itself.

2 -  Disputes over the amount of fuel in the tank on collection and delivery (see below). You should be aware that bringing back an empty tank option is likely to see you paying far more for the fuel than if you bought it at a local filling station.

3 - Issues over claims against the person hiring the car after it has been delivered back (see below) and note that rental companies hold your credit card details even after you have brought the car back, so ensure you have a written confirmation that the car was in an acceptable condition.

Here is the ECC advice to people renting in the European Union but the broad principles should be borne in mind in any country where you are renting.

"Renting a car is often the most practical and convenient way of getting around whilst travelling in another EU member state. When booking car hire consumers are eager to save money, however it is important to also be on guard to avoid extra costs and unexpected surprises. Many complaints relating to charges for damages or problems with a rental car, insurance coverage and fuel policies. We've put together some handy car rental tips to help make the journey a bit smoother.

At the moment there is no industry specific legislation in the car rental sector. Consumers are protected by other instruments with more general scope such as the Unfair Commercial Practices Directive 2005/29/EC and Directive 93/13/EEC on Unfair Terms in Consumer Contracts

The hire company's fuel tank policy should be carefully noted.

Car rental tips – dos and don’ts when renting a car in the EU:

When looking for the best bargain, bear in mind that very often prices quoted online only contain the basics. Make sure you check what is included in the final quote and what is not. Pay special attention to airport and other location related surcharges as well as the insurance coverage.

Always check the cost of extras that you may need during your rental: child seat, additional driver, extra insurance etc.

Pay special attention to the fuel policy and make sure it is explained to you clearly before you confirm the booking:

COLLECT FULL RETURN EMPTY POLICY implies that no refunds will be paid for unused fuel even if the whole tank was paid for upfront. As it is impossible to return the car empty, especially during short rentals, an alternative policy should be available on request.

COLLECT FULL RETURN FULL POLICY means that the vehicle should be provided with a full tank of fuel. Unless the consumer was clearly notified within the Terms & Conditions when booking the car, fuel should not be prepaid. It should be a consumer’s responsibility to refuel the car with the correct fuel type before it is returned. If the vehicle is not returned with a full tank, the consumer should bear the cost of refuelling.

Check age restrictions,

Check the cancellation policy.

When renting abroad, familiarise yourself with the rules of the road.

Normally a staff member should check the condition of the car upon collection. At this time all damage noted will be indicated on a special check-list or diagram, and you will receive a copy this document. If a staff member is not available to inspect the rental car, it is very important that you inspect it yourself, if any damage is present, make a written note of this and have it signed by an employee of the car rental company before you leave the premises.

Always request information on the policies in place in the event the car breaks down or, you are involved in an accident. Understand what is and is not covered under the insurance policy, also what excess may be charged to your credit card in the event of a claim.

Ensure you clarify what type of fuel can be used in the rental car.

If the car breaks down, call the car rental company and follow the instructions provided. Do not repair the vehicle yourself without prior authorisation.

In case of an accident, you should always note down the names and addresses of everyone involved. If anybody is injured, or when there is a dispute over who is responsible, you should notify the police. Contact the car rental company immediately.

Try to return the car during the working hours of the car rental company and have it inspected by a competent employee. The condition of the vehicle should be confirmed in writing and signed by the representative of the company and the consumer.

If you are returning the car outside the working hours of the car hire company, you should park it in the designated area. You can take pictures of the vehicle as confirmation that it was returned in good condition.

Cars returned outside working hours are inspected for damage on the following day and therefore the excess can still be charged to a consumer’s credit card.