The government is investigating a Queenstown park built on a former landfill and designated for housing development.
Warren Park on Gorge Road has been closed for five days for soil testing.
The Queenstown Lakes District Council has been using the large grassed reserve as an overflow carpark over summer, but closed it yesterday, saying a government ministry would be doing some investigative work.
Warren Park is built on a landfill that closed in the 1980s.
The Ministry of Business, Innovation and Employment said it was doing geotechnical testing across the reserve and the Wakatipu High School site next door to see if they were suitable for new houses.
The school is already scheduled to move next year to a new site in Frankton.
The ministry said the testing was part of a project identifying vacant or under-utilised Crown-owned land for housing.