Nora's disappearance triggered a massive search effort involving drones, sniffer dogs, multiple countries and more than 350 searchers, Malaysian police said.
National deputy police chief Mazlan Mansor earlier told a news conference that the body, which "was not in any clothing", was found by volunteers registered with the rescue team Tuesday afternoon in an area that had previously been searched by rescuers.
"All at the Lucie Blackman Trust are thinking of the family and continue to support them as they come to terms with this news", the charity said.
The Lucie Blackman Trust will help the family bring their daughter back home if the body turns out to be Nora's, Searle added.
He said the remains had been winched by helicopter to a hospital mortuary, where her family were due to identify her.
Her family said it would be extremely unusual for the reserved youngster to have wandered off on her own.
The window was also open in the room that Nora had been sharing with her two siblings. "We are extremely distressed and anxious and pray for her safety", it said.
A statement released on Tuesday said: "Nora's family believe she has been abducted".
Nora attended St Bede's Catholic Church in Clapham Park in south London, which has been holding vigils for her since she went missing.
"It is possible she has been seen or taken in by somebody and is unable to communicate, so we urge everyone who can to share our appeal poster and social media appeals".
According to police sources, the body was found fully intact.
During the search, recordings of Meabh's voice were played using megaphones and loudspeakers, in the hope Quoirin would recognise it.
Quoirin lived with her family in London but carried dual Irish and French citizenship. I'd like to pay tribute to everyone who searched for Nora. She is not independent and does not go anywhere alone.
Ms Quoirin explained to the press on Monday, Nora was their first child.