US federal agencies are to join forces with police to enhance security for a New Year's Day event in Pasadena, California, following the deadly mass shooting in San Bernardino.

According to US law enforcement officials, more than two dozen federal agencies are to help the police with extraordinary security measures planned for the annual Rose Parade event which includes more than a dozen armed tactical "rapid-response" teams posting along the parade route together with dozens of surveillance cameras, bomb-sniffing dogs and radiation-detection devices, Reuters reported.

"Although no specific credible threat has been made against the event, the precautions being taken mark the largest security operation in the 100-year-plus history of the Rose Parade and Rose Bowl," Mark Selby, Homeland Security's deputy special agent, said on Monday.

Selby referred to the terrorist attack in California, which claimed 14 lives on December 2, noting, "The San Bernardino event sort of upped the ante."

Spectators are expected to show up in Old Town Pasadena, north of Los Angeles, for the 127th Tournament of Roses Parade.

Police Chief Phillip Sanchez noted that two dozen undercover officers will patrol the parade route and several dozen surveillance cameras are to monitor the event.

Automatic license-plate reading devices will also be set up to collect data on suspicious vehicles in the area, police officials said.

Rose parade is part of America's New Year Celebration which includes flower-covered floats, marching bands, and equestrian units.