Police have spoken with a man who has come forward claiming Keli Lane left her baby Tegan in bushland 14 years ago.

The man contacted prominent Sydney criminal lawyer Chris Murphy after the former water polo champion was sentenced last week for murdering her newborn daughter.

According to Mr Murphy, the cabbie said he picked Lane and the baby up at Auburn Hospital and Lane left the baby in bushland on the way to Manly.

State crime command officers on Monday said they had spoken with the man, who they said had never come forward with the information before.

"This is the first time this man has come forward," a state crime command spokeswoman said.

Police have spoken "briefly" with the man and a preliminary assessment of his information was being carried out, she added.

A formal assessment would be carried out "to determine the validity of the information", the spokeswoman said.

Mr Murphy told Macquarie Radio he did not know if the taxi driver was telling the truth.

"If he tells a story to police that are lies, he'll be charged with creating public mischief and we've all been part of a horrible injustice," he said.

The taxi driver said he collected Lane and the baby at Auburn Hospital and stopped at her request on River Road.

He said Lane then got out and left the baby in an area of houses and bushland before they continued on to Manly.

After the taxi driver dropped her off, Mr Murphy said he noticed she left a baby bag with nappies in the back of the car.

"He called out to her that she'd left the stuff behind. She said, 'I don't need it and left'," Mr Murphy said.

"He said his suspicions were aroused."

The cabbie then went back to where the baby had been dropped off and found Tegan wrapped next to a tree with a bottle beside her.

A woman who was also there told the taxi driver she would mind the baby, Mr Murphy said.

Lane was last week jailed for at least 13 years and five months for murdering Tegan.

- AAP