The parents of a Sydney toddler who disappeared over six years ago are not giving up on their search for their baby, even increasing the reward they would give to anyone who could give valuable information on the disappearance from $100,000 to $250,000.

Police reports indicate Rahma El-Dennaoui was only 19 months old when she was taken from a bed she was sharing with her two sisters at Lurnea in Sydney in November 2005. The room's fly screen was cut to make an opening which police said was big enough for a person to fit in.

Homicide Squad Commander Michael Willing told ABC officials have no idea whether the girl is still alive.

"After six-and-a-half years, the investigation has been extensive but we've found little clues to solve this particular case," he said adding the circumstances surrounding the disappearance remained hazy but detectives have not given up on the case.

"We've considered everything from her being abducted to her being taken overseas...We're keeping an open mind. We're not discounting anything at this point," he said.

In May 2007, New Idea magazine put up a $20,000 reward for relevant information on Rahma's disappearance. Robyn Foster, the magazine's editor-in-chief, noted the similarities between Rahma's case and that of Madeleine McCann, which made her very interested in the case.

Madeleine is a British girl who went missing from an apartment just before she turned four years old.

Anyone with information on the toddler's disappearance may contact Crime Stoppers on 1800 333 000.