It means Beatles fans who pass the site on bus tours will now be met with 10ft (3m) high replicas. The charity said fans would still get an "authentic experience" with a view of the former home.
Replicas of the 100-year-old wrought iron gates have been made by metal work specialist Jim Bennett, from Aigburth, and gifted to The Salvation Army. The originals are being taken to a secret location for storage, but are expected to eventually be auctioned.
"Although care has been taken to ensure the original gates to the site have remained in good condition, inevitably time has taken its toll," said Maj Ray Irving, director of social services for The Salvation Army. "This means that the original gates can be kept safe from further deterioration and with the replica gates in place, allow for an authentic experience for the many thousands of people who come on a 'musical pilgrimage' to Strawberry Field."