A ''big black'' wild pig at the centre of New Zealand menaced a group of girls earlier this week before tempting many would-be urban hunters on Friday afternoon, but a Nelson City Council pig hunter is on the job.

Bridgette Bell, an Otago University student home for the holidays, said she was on her way to the Botanical Gardens with friends Georgia Wright and Giovanna Martin on Tuesday when they spotted the pig near the top of the hill.

''It kind of looked like a big, black, shaggy dog. We didn't recognise that it was a pig at first.''

She estimated it would have weighed about 50kg. Ms Bell said the trio did not move off immediately when they noticed the snout and hooves as they wanted to take a picture of the animal, but before they could seize their opportunity, the pig started to charge.

''It gave us a bit of a fright, it kind of snorted at us,'' Ms Bell said.

The three friends ''sprinted'' down the hill towards the Botanical Gardens to escape the pig. Ms Bell said she was not sure when it stopped chasing them, but it had definitely given up by the time they sought refuge on top of a picnic table.

''We got the fright of our lives but it was hilarious afterwards,'' Ms Wright said.

She said she had been fielding emails inquiring after the size of the pig and whether it would be worth hunting following the incident.

Pigs have been seen before near the reserve, and the NBS Nelson Striders still celebrate an incident where a pig threatened seven runners nearly 20 years after the fact.

In 1994, an agitated boar chased seven Striders up a bank in the Maitai Valley before Maitai Dam caretaker Trevor Ruffell drowned it with his bare hands.

The Nelson Mail's Facebook page exploded with more than 45 comments after the search for the pig went up on Friday afternoon.

''Quick, someone domesticate that swine,'' said one commenter.

''Just my [ex-partner] on holiday - don't worry, she's harmless,'' quipped another, while many more alerted their friends and family to the proximity of tasty wild pork.

Nelson City Council representative Ali Hamblin said it was ''not uncommon'' for pigs to come closer to town during cold weather. She said the council had an experienced pig hunter out looking for the animals and one was removed earlier this week, but only those with a council permit could hunt on reserves.

Ms Hamblin warned that people should not approach pigs or let their dogs chase them as the animals could be dangerous. Anyone who spots a pig should report it and its location to the council by calling 546 0200.