This area is called 'Henderson Park' and is used for equestrian sports, according to https://www.goredc.govt.nz/our-facilities/parks-and-recreation/sports-and-recreation/gore-and-mataura-sports-fields/

I am not certain what the exact borders are and if the area has other uses. 

leisure=horse_riding and/or leisure=pitch or landuse=recreation_ground or leisure=park could fit this land use.