A campaign against plans to drill for oil off Spain's Canary Islands has united politicians, environmentalists and personalities including the mother of Hollywood star Javier Bardem, a native of the archipelago.

An online petition launched on Monday against the plan by Spanish energy giant Repsol to prospect for oil off the islands had drawn more than 33,000 signatures by Tuesday afternoon.

In a manifesto read out in Madrid Monday by Pilar Bardem, the Oscar-winning actor's mother, campaigners said the project threatened the Canaries' vital tourism sector.

"The drilling constitutes a serious threat to the natural assets of the islands, to its economy and its supply of drinking water, to its tourism and therefore to its present and future inhabitants," said Pilar Bardem, herself a well-known actress in Spain.

She was among several artists to throw their weight behind the campaign along with non-government groups such as Greenpeace, authorities including the Canaries regional government, local fishermen's guilds and Spain's main opposition Socialist Party.

The campaigners said Repsol planned to drill nine kilometres (six miles) off the island Fuerteventura and 18 kilometres off Lanzarote, in a zone of seismic activity, much of it classed as a natural reserve.

Home to more than two million people, the eight Canary Islands welcome millions of foreign tourists every year.

The islands are nevertheless suffering more than most of Spain from the recent years of recession, with a regional unemployment rate of 35 percent.

National Industry Minister Jose Manuel Soria, who also comes from the Canary Islands, said the oil project would "introduce an extra economic activity" to the region.

The campaigners said the risk of an oil leak like the one that struck in the Gulf of Mexico in 2010 threatens the whole archipelago, which draws all of its drinking water from the surrounding sea.

The project was currently nothing more than "research and exploration, not at all extraction of oil or gas", a spokesman for Repsol, Marcos Fraga, told AFP on Tuesday.

He said Spain was the country in Europe with the biggest dependency on foreign oil and gas, equal to four percent of its gross domestic product.

"What country would not want to know what natural resources it has?" he added.