Dean Verberckmoes was reported missing by his family after his babysitter failed to drop him off at his grandparents' house.

Police said the child's body was found at Neeltje Jans in Zeeland province on Monday after officers issued an amber alert with the description of the toddler and a photograph.

A 34-year-old man had been earlier detained by police.

The boy was last seen in the Belgian city of Sint Niklaas near Antwerp with a man, identified as Dave De K by Dutch media including the NOS public broadcaster and NL Times.

The child's mother, Elke Verberckmoes, told Belga he regularly looked after Dean and his younger sister.

Belgian prosecutors told the news agency he was given a 10-year jail sentence in 2010 for abuse which led to the death of a two-year-old. He served eight years and his sentence ended in December 2018.

A large-scale search spanning the two countries was launched after Dean was reported missing.

Dutch police said the suspect was arrested in the town of Meerkerk, south of Utrecht, about 75 miles north-east of where Dean was found.

"Once at that location, a man was found, who turned out to be the missing 34-year-old Belgian. The four-year-old boy was not with him at the time," police said.

It was then that officers issued the amber alert.

"The police investigation pointed to a possible crime scene on Monday evening... and a police helicopter also joined the search," Dutch police said.

"Around 10pm the lifeless body of a child was found."

On Twitter, police in Zeeland said: "We thank everybody who helped and are sending condolences to his family."