Travellers to Spain are being told by tourist board officials to take their own sandwiches and lots of water in case they are caught up in a series of strikes due to hit the hotel and catering industry there this month and in August.

While travel companies are devising contingency plans, which could see tourists getting food packs delivered, and, in some cases, compensation or refunds on their holidays, independent travellers could be left to fend for themselves.

The strikes over pay and work conditions on the Balearic islands and the Costa del Sol are planned for 26-27 July, 5-7 August and 16-18 August although negotiations are still taking place. If they go ahead, tens of thousands of hotel maids, waiters and bar staff will not turn up to work, leaving holidaymakers to make their own beds and to find restaurant doors firmly closed.

'People should make sure they bring lots of water with them and some sandwiches,' said a spokeswoman from the Balearics Tourist Office. 'People might have to make their beds in certain hotels. In some areas, you probably won't be able to get food at hotel bars and restaurants on the days of the strike.'

Both Thomson and MyTravel said they were looking into the situation. Though they were not currently allowing customers refunds or changes to their plans, they said they were looking at implementing measures that could include food packs for travellers, restaurant vouchers and putting extra staff on duty. Customers are to be alerted about any problems before they travel.

Spanish specialist Mundi Color said that if the strikes went ahead, it would even let tourists reschedule or cancel their holidays with a full refund; if holidaymakers decided to go ahead, they might be entitled to some compensation.

Independent travellers, however, are unlikely to fare so well. Eileen Brennan, principal lawyer from the Consumers' Association, said it might be more hassle than it was worth for anyone to pursue compensation claims against hotels they had booked themselves. 'It is the same when you buy anything abroad,' she said. 'The hurdles you have to overcome to pursue your rights are much more difficult.'

A spokesman from the Association of British Travel Agents said that holidaymakers generally reacted with a stiff upper lip to strike problems. 'Making your bed in the morning is an inconvenience but not really a big deal,' he said.

However, Jose Luis Gurra, secretary general of the Spanish Hotel Federation, said he thought the strikes were unlikely to go ahead. 'Even if there are strikes, they will have little effect - tourists will still have essential services, including hot food,' he said.