US police have recaptured two mistakenly freed convicted murderers, who used forged documents to get freed from a Florida prison.

Joseph Jenkins and Charles Walker, both 34, were detained on Saturday night at the Coconut Grove Motor Inn in Panama City, a tourist area in Florida.

The men, both serving life sentences, walked out of the Franklin Correctional Facility without anyone realising the paperwork was forged.

Jenkins, who was released first on September 27, registered as a felon three days later at an Orlando jail, following the law.

The killer of an Orlando man, Roscoe Pugh, during a robbery in 1998 had his photograph taken and his fingerprints were checked against a database to make sure he did not have any outstanding warrants for his arrest.

Walker was released a week later, on October 8, and prison officials took him to a bus station, buying him a ticket.

He had been in prison since his conviction of second-degree murder in the 1999 Orange County slaying of 23-year-old Cedric Slater.

The mistake has been discovered after one of Pugh's relatives contacted the state attorney's office to let them know Jenkins had been released.

Prosecutors reviewed Jenkin's case file and discovered the forged paperwork. They also found out Walker's documents were also falsified and a manhunt was launched for both men.

Hours before the recapture, their families had held a news conference urging them to surrender.

Authorities have started an investigation into who was responsible for the mistaken releases.

"Now that we have them in custody, we're hoping to get something from the interviews with them,'' Gerald Bailey, the Department of Law Enforcement Commissioner in Florida, said.

The Corrections Department has already changed the way it verifies early releases and prison officials will now verify with judges before releasing prisoners early.