PORTUGUESE public prosecutors have agreed to reopen the Madeleine McCann investigation.
The country's Attorney General's office confirmed it had approved the move following a request from Portuguese police.
The new investigations are expected to be carried out by the Policia Judiciaria police force based in the Algarve town of Portimao.
A spokesman for the Attorney General's office said in a statement released just around 1pm local time: "The Public Ministry has determined the reopening of the inquiry relating to the disappearance of Madeleine McCann following a request from the Policiia Judiciaria."
Madeleine McCann's parents Kate and Gerry said today they are "very pleased" that Portuguese authorities plan to re-open their investigation into her disappearance and hope that it will uncover "the answers we so desperately need".
Detective Chief Inspector Andy Redwood, who is leading the Scotland Yard team, Assistant Commissioner Mark Rowley, and Madeleine's parents Kate and Gerry met officers in Lisbon last week to be briefed on the Portuguese case.
The new Portuguese lines of inquiry are separate to those being chased by the Met.
Mr Rowley said: "The meeting was very positive, and we and the Policia Judiciara have a shared determination to do everything possible to discover what happened to Madeleine.
"Colleagues in Portugal fully shared with us the developments in their review, and the fact that they were taking the significant step of applying for the investigation to be formally reopened.
"This is a welcome development, but both sides of the investigation are at relatively early stages, with much work remaining to be done.
"This new momentum is encouraging, but we still have a way to go, and as with all major investigations, not all lines of inquiry that look promising will yield results.
"Today's development is good news. Combined with the formal reopening of the Portuguese investigation today, and our ever closer working relationship, I believe that we have the best opportunity yet to finally understand what happened to Madeleine."
On Wednesday Metropolitan Police Commissioner Sir Bernard Hogan-Howe defended the way Portuguese police handled the initial investigation into Madeleine's disappearance.
She vanished from a holiday apartment in Praia da Luz in May 2007 as her parents dined in a nearby tapas restaurant.
Speaking on LBC 97.3, Sir Bernard said: ''I think sometimes these things at the beginning can be very difficult to deal with, you don't know exactly if the child has just wandered off. It can be very difficult to know if you've got a very serious crime.
''I'm sure for them that must have been a challenge. Anybody can go back after two, three, five, six years and say 'why didn't you do that'? That's easy in hindsight.
''We don't like it when it happens to the Met, and I'm certainly not going to do it to the Portuguese."
Refreshed appeals were made last week as part of the British investigation, with Mr Redwood appearing on television in the UK, Holland and Germany.
He revealed that his team had discounted a previous sighting by the McCanns' friend Jane Tanner, which was thought to be an abductor carrying Madeleine away and had been put at the centre of the Portuguese investigation.
His team managed to track down the man - an innocent British holidaymaker - and instead decided to focus on a second suspect who was also seen with a child in his arms.
Officers also said they would like to trace a number of fair-haired men who were seen near the apartment at the time, and are looking at a surge in burglaries in the area as well as bogus charity collectors.
An appeal is due to air on Irish television later this month.
Home Secretary Theresa May told the BBC News channel: "The police have been working very closely with the Portuguese police and I think they've been developing the evidence and the leads and possibilities of leads that we've seen coming forward recently.
"I think we've got very good collaboration between the Met and the Portuguese police and I think that is now starting to bear fruit.
"I hope it will enable a resolution of this terrible thing that happened to the McCann family, so that her parents are able to know finally what did happen to Madeleine."
Portuguese police said that a review team had been working since March 2011 to look back through information from the original investigation.
This process had uncovered potential new lines of inquiry.