Police and explosives experts have been unable to clear an old mortar shell found at a house on Pukenui Road in Epsom, but have taken the cordons down overnight.
Residents from several streets near the house were evacuated and cordons were put up after the shell was found shortly after 5pm on Thursday.
Many people stood outside the streets taped off by police through the evening awaiting clearance to go home.
But shortly before 10pm police said the teams working on it had been unable to remove the shell so far, and safety precautions had been set up at the site, with the work to continue on Friday.
Officers had taken down the cordons for the night, and most residents were being allowed back to their houses until Friday morning. Though the people who lived at the house the shell was found at were staying elsewhere for the night.
"Police and the [Defence Force] Explosive Ordnance Disposal team will return in the morning, and cordons will be reinstated to allow the EOD team to dispose of the item safely," police said in a statement.
"A scene guard will be in place at the effected property overnight."
An RNZ reporter at the scene during the evening said some had been waiting at the site for up to two hours.
Jono Pryor was looking forward to a night alone, with his family away in Tauranga, but his plans were quickly thwarted.
"I walked out of the driveway with the dog and saw - it felt like 18 police cars, and they were just walking up the road evacuating everyone out of their house," he said.
"We're just sort of all lingering around like bad smells waiting for the cordon to be lifted."
Police said people had been asked to avoid the area as specialists were probing the object.