The area was undeveloped land until Cook County Hospital was demolished in 1988.
Demolition material from site buildings was disposed in the valley, which is now known as Tūranga Gardens.
“This is not a safe area for anyone to walk through and there are barriers in place across the entrances.”
Ms Frey says following the report, Council staff will look at options to manage the site moving forward, which will be dependent on funding.
“We’ll update the public once we know more.
“We understand Tūranga Gardens is a special reserve for many, and in particular a very hardworking crew who’ve volunteered thousands of hours to keep it looking beautiful before the cyclone hit.
“We acknowledge you all, and that drives our motivation to find a solution for the community.
“Please be patient while we figure out cost-effective remediation options, and please stay out of this area until further notice.”
The gardens were developed in 2001 by the Tūranga Lions Club, with supporting donations from the Williams Family Trust and Gisborne District Council.
Since then, other people and businesses also came on board to donate.