Portugal's public prosecutor dropped the case on the disappearance of British girl Madeleine McCann in the absence of any evidence on Monday, and cleared her parents and another Briton of suspicion of involvement.

Chief prosecutor Fernando Pinto Monteiro said in a statement that Gerry and Kate McCann and Robert Murat, who lived in the same resort in southern Portugal's Algarve region where the three-year-old vanished 14 months ago, were all cleared.

"The public prosecutor's office has determined that the investigation into the disappearance of Madeleine McCann be archived, due to the lack of evidence of any crime being committed by the suspects," the statement said.

"The case can be reopened by the public prosecutor's office, or following a request from an interested party, if new evidence materialises," it said.

The McCanns welcomed the decision and said they would not give up the search for their daughter.

"We welcome the news today, although it is no cause for celebration," Kate McCann told a news conference in Britain, reading from a statement.

"It's hard to describe how utterly despairing it was to be named 'arguido' and subsequently portrayed in the media as suspects in our own daughter's abduction and worse.

"Equally, it has been devastating to witness the detrimental effect this status has had on the search for Madeleine.

"We look forward to scrutinising the police files to see what has actually been done and more importantly what can still be done as we leave no stone unturned in the search for our little girl."

Madeleine disappeared from a bedroom in her family's holiday apartment in Praia da Luz on May 3, 2007, a few days before her fourth birthday.

The case grabbed international headlines, especially after police named her parents as suspects.

Police have failed to find either the girl or enough evidence to charge anyone and presented their final report to the prosecutor on July 1. The McCanns have led a high-profile global hunt for their daughter.

Murat, who was named a suspect by police, last week won 600,000 pounds in libel damages from 10 British newspapers that had accused him of being involved in the girl's disappearance.

In March, the McCanns won 550,000 pounds in damages from the Daily Express and Daily Star over stories suggesting they might have killed Madeleine. The papers issued front-page apologies.

Gerry McCann told reporters that he and his wife had no intention of returning to Portugal in the near-term, and did not rule out taking legal action against Portugal's authorities.

Rogerio Alves, the McCanns' lawyer in Portugal, told SIC television that the outcome was to some extent gratifying, although the girl's fate remained unknown.

"In view of the fact that the process had been turned against the parents, the result is gratifying and it's a victory knowing that they are no longer suspects," he said. "There is a marginal, secondary kind of satisfaction, but an important one."

Alves declined to comment on a book due to be launched on Thursday by former chief investigator Goncalo Amaral.

Amaral, who was removed from the case, has said he will reveal previously unknown facts and shed new light on the case.