Spanish King Juan Carlos apologised Wednesday for a hunting trip to Botswana that sparked indignation in recession-hit Spain, as he emerged on crutches from hospital after breaking his hip on the visit.

"I am very sorry. I made a mistake and it won't happen again. Thank you for your interest," the 74-year-old monarch said during his televised departure from a Madrid hospital.

Looking serious, the king said he was feeling "much better" after the hip replacement at the capital's USP San Jose Hospital and was looking forward to resuming his official duties, before exiting the hospital on crutches.

Doctors discharged the head of state a few hours earlier, saying in a statement that after a "very satisfactory" recovery since Saturday's operation he was now able to get around by himself.

The king, though widely respected for his role in steering the country to democracy after the death of General Francisco Franco in 1975, was harshly criticised for his Botswana hunting trip.

Many were angered by the extravagance of the holiday, coming at a time when millions of Spaniards are suffering in recession, and the fact that he was hunting big game.

Fuelling the scandal, conservative newspaper El Mundo reported on Wednesday that the trip was paid for by a Saudi magnate, Mohamed Eyad Kayali.

Leaders of the two main political parties have refrained from explicitly criticising or defending the king, but newspapers were not so forgiving.

El Mundo branded the trip "irresponsible" and "inopportune" in an economic crisis.

"The sight of a monarch hunting elephants in Africa when the economic crisis in our country is causing so many problems for Spaniards does not set a good example," it said, giving vent to unusual criticism of the king.

"This is something totally new," said Antonio Torres del Moral, an expert on the royalty at Madrid's UNED university.

"To my knowledge, never in our history has there been an episode where the king apologises for his behaviour."

Many papers published a photograph dating back several years of Juan Carlos posing with an elephant during a hunting trip.

Animal rights groups protested near the hospital during the king's convalescence, holding photographs of elephants and baby seals.

The Spanish branch of the wildlife charity WWF, which names the king as its honorary president, said this week it would make comments to the royal palace and reiterate its commitment to the conservation of elephants.

A petition on the online forum Actuable listed 40,000 signatures urging the king to give up his presidency of the Spanish WWF.

Botswana authorities confirmed Monday that Juan Carlos fell and broke his hip during an elephant hunting expedition in the north of the country but said he slipped in his chalet, not in the bush.

Doctors said he had tripped on a step at 2:00 am on Friday morning in Botswana, but gave no further details of the accident.

Juan Carlos has suffered a troublesome few months marked by an embarrassing corruption scandal implicating his son-in-law, the Duke of Palma, Inaki Urdangarin.

In the wake of the Urdangarin scandal, the king said in his Christmas speech that public figures should observe "appropriate behaviour".