The New Zealand falcon, or karearea, attack by making fists with their feet and dive-bombing other birds.

Native falcons are rare around Wellington and would usually be made welcome – but not when they're dive-bombing walkers.

A pair of falcons nesting around Te Ahumairangi Hill, formerly known as Tinakori Hill, have twice attacked walkers on a track, prompting Wellington City Council to put up warning notices.

"Over the last few days we've had two people who've had altercations, shall we say, with the falcons," council urban ecology team leader Myfanwy Emeny said.

The birds were known to become territorial when they had eggs waiting to hatch.

"They defend their territory as any stroppy little falcon likes to do."

There had been three pairs of the birds recorded in the Wellington area over the past few years.

"They're a bush falcon and they hunt on the wing ... they basically make little fists with their feet, and they fly in behind a bird really quickly and dive bomb it, and knock them on the back of their head with their feet, and knock them to the ground."

That was "kind of what they've been doing" to the walkers, she said.

The first attack was on Tuesday, followed by another on Thursday.

She said the falcons, or karearea, had "made contact" with the walkers they attacked: in the second case, the walker was bombed by both birds.

"They came in together, from the description of the attack. One attacked him, and then the other one came in from the other side of the track, then perched up on a branch."

Falcons were bolshie birds, she said, being a raptor species.

One of the people attacked got "a few scratches", while the other just got a fright.

The karearea is the only remaining bird of prey endemic to New Zealand, with pockets of the remaining population scattered around the country.

The Department of Conservation says the bird is capable of flying at speeds over 100kmh, and can catch prey larger than itself.

The council was placing warning signs for walkers on the hill, which would include a request for people to keep dogs on leashes.

Falcons nest their eggs on the ground, which made them vulnerable to dog attacks, Emeny said.

"They are one of our threatened species, so we're actually really lucky to have them breeding a stone's throw away from the CBD."

Emeny said the council would be advising people to steer clear of the nest for the next two months, with the season lasting up 90 days.

"They are just phenomenal little birds, aggro at times, but it's all part of their personality."