Speaking to reporters a day after the Spanish tennis federation (RFET) said it would sue French TV broadcaster Canal+ for "unacceptable and damaging insinuations" in a cartoon about Nadal, the world No 2 said he found the attacks "sad".

"It's the kind of humour that for one day is fine but if it is repeated over and over again it's not right and I think it oversteps the line a bit," Nadal said at a training session in his home town of Manacor on the island of Mallorca on Thursday.

"I don't think it's just one media, it's a general campaign by the neighbouring country," the six-times French Open champion added.

"It's sad to see a campaign like that against something that has cost so much to achieve.

"There's no question of pills or syringes or anything like that I can assure you."

The Canal+ sketch from their show "Les Guignols", or "The Puppets", showed a life-size likeness of Nadal filling up his car's gas tank from his own bladder before being pulled over by traffic police for speeding.

"Spanish athletes. They do not win by chance," is flashed on the screen surrounded by the logo of the RFET and several other Spanish federations, including soccer and cycling.

The RFET said it planned to sue the broadcaster for the attack on Nadal as well as for reproducing the federation's emblem without permission.

Canal+ has broadcast several other cartoon sketches implying Spanish athletes use illegal drugs, including one about cyclist Alberto Contador, who was handed a two-year ban on Monday after testing positive for a banned anabolic agent during his victorious 2010 Tour de France campaign.

Contador, who was stripped of the title, denies wrongdoing.

"I think it's an issue one shouldn't comment on personally but collectively," Nadal said.

"I think in this case it's the institutions who have to defend us because I don't think it's a campaign against me or any other individual but one against Spain in general.

"I don't think it's just Canal+ who does it. There are other media who are also joining in."

Spanish Foreign Minister Jose Manuel Garcia-Margallo and European Commissioner Michel Barnier, a Frenchman, were asked about the sketches at a news conference in Madrid on Thursday.

Garcia-Margallo said the government was very concerned about the "succession of images" coming out of France that had "denigrated Spanish sport".

"The videos are in extraordinarily bad taste and show a profound lack of ethics, not to say they lie," he added.

The Spanish ambassador in Paris would be writing to French media, and to the director of Canal+ in particular, to express Spain's displeasure, he added.

Barnier said French politicians had learned to distance themselves from cartoons like those shown on Canal+ and to avoid commenting on them as it did not generally help.

Canal+ could not be reached for comment.