"I'm not going to comment on what is an ongoing investigation, except to say that this is a very concerning situation," Ms Keneally told journalists on Wednesday
"This is a family's worst nightmare.
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"Right now we are allowing police to get on with their investigations."
Police said on Tuesday they were looking at whether the Department of Community Services or other government agencies had any dealings with the family.
Ms Keneally said she could not guarantee that no child would fall through the cracks of the state's child protection system.
"As I have said, as other ministers for community service have said, there is no child protection system in the world that can guarantee the absolute safety of every child," she said.
Kiesha was last seen at 9.30pm (AEST) on Saturday when her mother, Kristi Abrahams, put her to bed in pink pyjamas and a purple Pumpkin Patch jacket at their unit in the western Sydney suburb of Mt Druitt.
She was reported missing on Sunday morning after her mother discovered her bed empty and the front door ajar.
The missing girl, described as a happy, quiet child, had not attended school recently and was known to government agencies including the Department of Community Services.
