A pilot scheme to test the DNA of dog poo to try and catch owners who fail to clear up after their pet has begun.
Samples of dog mess will be collected by officers from the London Borough of Barking and Dagenham Council and park rangers during the next three months.
DNA will then be compared to a database of registered owners.
Registering dogs is voluntary for owners but microchipping will be required by law from April.
The pilot is being carried out in local wards Abbey, Mayesbrook and Longbridge.
The council said it will assess the scale of the dog mess problem during the trial and whether people who fail to come forward to register their pets are responsible for the majority of it.
Councillor Darren Rodwell at Barking and Dagenham Council said: "This scheme, which is in response to concerns raised by our residents, is about bringing considerate owners on board with us now, enabling us to gather evidence so we can get tough on inconsiderate owners later."
Registering pets with animal DNA specialists PooPrints is free for the first 1,000 registrations, the council said.
Gary Downie, managing director of PooPrints UK said the technique was useful "in this age of austerity".
He said it would ensure dog owners who do clean up after their pets are "not tarred with the same brush by the actions of those dog owners not playing by the rules".