A hacker set off all 156 emergency sirens in Dallas which wailed for 90 minutes overnight.

The hacker tricked the system into sending repeated signals 60 times from 11.42 pm until 1.17am on Saturday morning.

Rocky Vaz, director of the city's Office of Emergency Management said the hacker was from Dallas, USA Today reported.

However, the culprit has yet to be found.

The hacker created havoc in the city. The sirens are normally used to warn of severe weather, such as tornadoes.

Anxious residents deluged the 911 emergency system with phone calls, with 4,400 being made in three and a half hours.

Mike Rawlings, the city’s mayor, said the city would find and prosecute whoever was responsible.

"This is yet another serious example of the need for us to upgrade and better safeguard our city's technology infrastructure," he posted on Facebook.

"It's a costly proposition, which is why every dollar of taxpayer money must be spent with critical needs such as this in mind. Making the necessary improvements is imperative for the safety of our citizens."

The emergency siren system is expected to be functioning normally by Monday afternoon.