British police conducting a global search for toddler Madeleine McCann, who disappeared in Portugal six years ago, said they had received hundreds of calls following a new television appeal that suggested she was snatched in a planned abduction.

McCann, then aged three, disappeared from her family's holiday apartment at the Praia da Luz resort in the Algarve in May 2007 while her parents dined with friends at a nearby restaurant.

Her disappearance sparked a search that gripped the world's media but, despite extensive appeals, her fate remains a mystery and a Portuguese police inquiry closed five years ago.

In a Monday television appeal on the BBC's Crimewatch programme, British detectives said they had pieced together a new sequence of events suggesting McCann was targeted by abductors.

They said they wanted to trace a number of men, including some thought to be either Scandinavian or German, while another line of inquiry is that she was taken after disturbing burglars.

Madeleine McCann e-fit images

Police released two computer generated images of a man spotted by an Irish family holding a child matching Madeleine's appearance and heading towards a nearby beach on the night she disappeared. (Metropolitan Police/Associated Press)

The TV appeal, which featured a reconstruction of the events, generated more than 730 calls and 212 emails, Detective Chief Inspector Andy Redwood said.

"Detectives are now trawling through and prioritizing that material. This will take time," he said in a statement on Tuesday. "We continue to appeal for information," he said, adding he would be repeating the appeal in Holland and Germany.

British police began their own inquiry in July, saying they believe that McCann might still be alive. In the TV appeal, Redwood said the Portuguese inquiry centred on a dark-haired man seen carrying a child by one of the McCanns' friends.

But Redwood said his team had ruled this man out and was keen to trace another man spotted about 45 minutes later by an Irish family holding a child matching Madeleine's appearance and heading towards a nearby beach.

Police have released two computer generated images of this man, as well as artist impressions of other men seen near the McCanns' apartment in the days and hours running up to Madeleine's abduction.