Adults who care for a child for longer than 28 consecutive days are required by law to register as a private foster carer.
Redbride Council is urging residents to register this week as anyone who doesn't register could be breaking the law.
Grandparents, aunts and uncles are exept from registering.
Cllr Alan Weinberg, Cabinet Member for Children’s Services said, “I urge anyone out there who is caring for a child for over 28 days to register.
"This is not about unnecessary nanny state intervention – it’s about keeping children safe.”
Currently in the borough there are 11 private foster carers who look after 12 children.
During registration the council checks the suitability of prospective foster carers and other members of the household to ensure the arrangement is safe for the child.
To register as a private foster carer call 020 8708 3781 or email CPAT.firstname.lastname@example.org.