Officers are working with the DVLA to probe the theft of the identities of 11,000 cars worth more than 13 million.
Mark Hooper said officers are recovering about ten faked log books per week and that up to 130,000 blank documents have not yet been found.
The papers went missing from the DVLA in 2006 and allow thieves to "clone" details of anyone's car. If they have stolen a specific model, they can make it look legitimate by using details of another car of the same make in the log book.
Mr Hooper, who is head of vehicle intelligence for Acpo, said: "We are working closely with the DVLA to investigate the theft of a large number of vehicle registration documents. Around 11,000 vehicles, worth over 13m, are estimated to have had their identities stolen over the past two and a half years, with innocent motorists the victims.
"There are some simple ways in which the public can protect themselves and we urge that every care is taken."
The DVLA said it runs a hotline for car buyers to double check that a registration certificate is valid.
A spokesman said: "We have done everything we can to quickly alert the public to the theft of these blank registration certificates and continue to work with the police.
"The DVLA has every sympathy with anyone who unwittingly buys a stolen vehicle. We provide every assistance to help people avoid this, including running an information hotline for the public to check whether a certificate may be invalid prior to the purchase of a vehicle."
A list of the serial numbers of the stolen log books is available on the DVLA website.