Several heavy street lamps have dropped to the ground in Wellington and the city council is scrambling to figure out what is wrong with them.

Former Wellington city councillor Chris Calvi-Freeman discovered the dodgy lamps and had huge concerns for residents' safety.

"Without a shadow of a doubt, you'd be killed stone dead," he said.

He started noticing street lamps out on Evans Bay Parade which runs along Wellington harbour a few months ago, which were fixed after he contacted the council.

"More recently I've noticed street lamps with the wires hanging out of the top of the column, and then the day before yesterday, I noticed a large LED lantern on the ground.

"I could see it was corroded and it had clearly fallen off the lamp column."

The lantern was about a metre long and weighed about 15 kilograms, Calvi-Freeman said.

He wanted council to check all of the 17,000 LED lamps, which were only installed in 2018.

He suggested they start in areas like Evans Bay, which were subject to high winds and salt spray from the sea, and then move on to high pedestrian areas like the CBD.

"The first duty of a city council is to keep its residents safe, and that has to come before everything else."

Wellington City Council spokesperson Richard MacLean said the council was aware of a "bad batch" of lamps before Calvi-Freeman's discovery, and engineers were still assessing the problem.

He hoped there would be more information today.

"We know that it's been happening sporadically around town," MacLean said.

"In most cases they haven't actually fallen, we've noticed they started drooping, so we've gone and fixed them."

MacLean estimated no more than three had actually fallen.

There could be about 100 lamps that were problematic, he said.

But he did not yet know why, suggesting it could be metal fatigue or problems with joints.

"We have a bunch of different light brands and designs, they're all LEDs but not all from the same manufacturer," he said.

"We will have to look around town and see if we can narrow it down.

"We're trying to confirm whether they're random, or a particular suburb or street."

-Lauren Crimp, RNZ