The men were rounded up after a tip-off from an informer, who called a police hot line in Athens. The informer said he knew the whereabouts of Ben - now called Andreos - claiming he was with a man in his fifties called Nikos, who has vanished from his home in Thessaloniki.
The men were arrested in Katerini, northern Greece, after they were allegedly caught trying to sell a child they had bought from a gypsy family.
Although the child is not Ben, police believe the men could be part of a child trafficking ring and that they might know where Ben is, and also give them more details about the man called Nikos.
But at her home in Foxhill, Sheffield, Ben's 23-year-old mother, Kerry, said: 'We have been crucified so many times in the past when we have allowed our hopes to build up. We are trying hard not to get over-excited by the news.
'But we could be on the verge of the breakthrough we have prayed for. I believe we are not far behind Ben now.
'I have never for one moment doubted he is still alive, and have always believed he was kidnapped and sold.'
Ben vanished in 1991 aged two-and-a-half, from the Greek island of Kos, where Miss Needham's parents were renovating a house.