Their work is bearing fruit. Wendy John, one of the founders of the Friends, told Auckland Council's publication Our Auckland: "Now the kereru (native wood pigeon) are back and we see way less possums and rats."
Their work has also led them to being named as the winner of last year's River Stories category of the New Zealand River Awards – a category to mark the most interesting and compelling story of a person or group working to improve the health of a river. The awards are run by the Cawthron Foundation.
Although Oakley Creek has been given a poor (but improving) rating in Land, Air, Water Aotearoa's (LAWA) analysis into the 10-year trends in water quality in New Zealand's freshwater rivers and streams, John says the area is special.
"We all need some connection with nature," she told Our Auckland. "Oakley Creek is a place in the middle of the city where you can go and do that. You feel miles away from anywhere and it's so special, it's a little gem really."
John was first introduced to the area while involved with a community group seeking to stop a motorway from going through the Oakley Creek catchment.
"There had been intermittent clean ups but nothing organised," she said. "The area was desperately in need of some TLC and protection; looking after it seemed like the automatic natural next step."
So in 2004 John and some like-minded people formed Friends of Oakley Creek. They took on the role of guardians and faced challenges from the beginning – "weeds, pest plants and animals, water pollution and rubbish in the creek – plus the area didn't have a profile."
Since then the group has organised monthly working bees and what started as planting and general clean-up now includes monitoring and pest control – along with regular contact and support from Auckland Council.
"We've planted around 65,000 native species and now monitor weta, lizards, birds and water quality as well as pests," she told Our Council.
Oakley Creek is the longest urban creek in Auckland and includes a 6m waterfall, the only one in the Auckland city area. It is surrounded by 50 hectares of almost continuous green space and is unique in that it is accessible to the public for almost its entire length.
Home to a wide variety of flora and fauna – including heron and eels – it was in pre-European times a vibrant ecosystem of wetlands, swamps and plentiful vegetation.
A report of the council's Puketapapa Local Board says urbanisation has significantly degraded the creek's ecology and water quality with downstream effects impacting the water quality of the Waitemata Harbour.
The report is aiming by 2040 to have the creek "run clear, healthy and clean through a ribbon of green forest" to allow swimming and wading. It also envisages the area once again being suitable for the collection of food, harvesting of natural resources and one providing a habitat for native plants and animals.