Portuguese police officers yesterday dismissed a tip-off that the body of missing Madeleine McCann was buried in scrubland about nine miles from where she was abducted after carrying out a search with sniffer dogs.

Starting at dawn, they cordoned off an area north of the tiny village of Arao, 15 kilometres from Praia da Luz.

For several hours, more than 30 Guarda Nacional Repulicana, 20 Policia Judiciara (PJ) and four specialist dogs examined the scrubland.

Cordons were established on all roads surrounding the search area, a desolate hillside covered in trees and wasteland just north of the main road to Faro. But by 9.30am the search had been called off and the letter dismissed.

Chief Inspector Olegario Sousa, from the PJ, said: "The search has been carried out. This clue has been completely checked and the result was negative so the investigation goes on."

He said the dogs had not found anything significant and denied claims that officers had dug up land.

The formal search was carried out two days after Portuguese police were told about an anonymous letter alleging Madeleine had been buried under a pile of rocks.

The letter, accompanied by a map marked with a cross, was sent to Dutch newspaper De Telegraaf on Monday.

The father of Madeleine said his Catholic faith would be "severely tested" if his daughter was not found safe and well.

Gerry McCann and his wife Kate have led a tireless campaign to try to find the four-year-old who was abducted from Praia da Luz 43 days ago.

They have leaned heavily on religion, but Mr McCann admitted the prospect of her not coming back would stretch their belief.

"If we don't get Madeleine back alive and well, I am sure our faith will be severely tested," he told The Tablet, a Catholic newspaper. "At the end of it, we will still have our faith and also comfort Madeleine will be looked after."