Part of Dereham Road, close to its junction with Bowthorpe Road and on the western side of the city, has also been sealed off by police.
A neighbour, who did not wish to be named, told the BBC she saw armed police arrive to make an arrest in the early hours of the morning.
“I saw some flashing lights and looked out of the window and they’d cordoned off the road,” she said.
“Then all I saw was a bunch of police officers in full gear with guns.
“They just said ‘get on the ground’.
“There wasn’t too much cufuffle but it was shocking to watch.”
She said a man came out of a house with his hands out and was arrested without “too much struggle”.
The operation took about an hour, she said.
Forensic officers have been seen entering a semi-detached house, inside the 35m-long (115ft) cordon.