A group of women - who have been taking part in Oxfam Trailwalker events for almost two decades - say they are sad the fundraiser is coming to an end.
The last-ever Trailwalker will take place in New Plymouth over the weekend.
The development agency said declining registrations and rising costs mean Trailwalker - which began in 2006 - was no longer viable.
The City Girls - who come from Pitararu, Tīrau, Whitianga and Auckland - were at the very first event in Taupō.
Kerry Farrant said they stumbled across trailwalking after sharing a family holiday together.
"We ended up going for a bit of a walk together and it grew from there. One of the team Lesley [Reece] said she'd heard about this event that was going to be starting in Taupō called the Oxfam Trailwalker 100 kilometre walk and somehow we ended up getting involved in it."
Trailwalker involves teams of four which sign-up to trek either 25, 50 or 100km over a 36-hour period.
The City Girls - who were in their 40s and 50s - initially went the full 100k.
"It was really hard but we ended up doing it [the 100km distance] 10 times so it must've been okay.
"We just go stuck in and did a whole lot of training and divided it up into 10km bits in our head. Yeah, it was hard work, but it was a very big sense of achievement when you finished."
Teams pay a registration fee of between $600 and $1000 and commit to fundraising up to $3000 depending on the distance they are walking.
City Girl Jan Bullot said the fundraising was the hardest part, but it did not hold her back.
"I love the fact that you get out and meet some really awesome people. There's a lot of awesome volunteers that spend a lot of time volunteering to help.
"Also Oxfam is a really good cause. I think we have donated ... fundraised close to $50,000 over our time involved with Oxfam."
Oxfam Aotearoa fundraising head Angela Janse van Rensburg said the City Girls personified what Trailwalker was all about.
She said the formula had raised $16 million since 2006 which the organisation had pumped into initiatives around the Pacific.
But times had changed since Covid-19.
"People just weren't as open to doing this event after that. You know our registrations numbers unfortunately fell and then with the economic crunch people find it hard to fundraise for the event as well.
"That on top of rising operational costs and ensuring that we meet the health and safety requirements to deliver this event ... all of that has had a massive impact."
About 125 teams were registered this weekend. In its hey day, Trailwalker attracted more than 300.
Now 65, Bullot had mixed feelings about the New Plymouth event.
"I think the family are quite pleased because I'm not disappearing all the time for training and away for weekends, but no it is very sad that it's come to an end and, yeah, it's just a huge shame. But I guess it's a sign of the times that it's wrapping up."
Farrant, 62, said there was no way the City Girls - who also included Lesley Reece, 78, and Margaret Kennedy, 79 - were missing this Trailwalker.
"It's been a big part of our lives and it's been amazing for our friendship as a group.
"We had said we weren't ever going to do it again, but when we saw that this was to be Oxfam's last time and that there was a 25km option we thought well we need to finish what we started all those years ago."
Oxfam Trailwalker starts at Waitara's seaside park with the 100km walkers setting off at 6.30am and the 25km and 50km walkers starting at 7am. All distances eventually finish at the TSB Stadium in New Plymouth.
They will travel along various routes through farmland, parks, forest, beach trails, bush, and neighbourhoods, depending on the distance.
The shortest distance (25km) will cross the finish line within nine hours, 50km teams should cross the finish within 18 hours and the 100km teams will cross the finish line within 36 hours.
Each distance has built in "checkpoints" where support crew can meet up with teams to provide meals, snacks, backrubs, moral support, and cheerleading.