Security has been stepped up around a Papakura sports complex after a suspicious fire damaged a grandstand yesterday morning.
The fire broke out at Massey Park just after midnight, damaging about a quarter of the Papakura Athletic and Harriers Club grandstand.
Firefighters and police suspect the fire was deliberately lit.
The grandstand - thought to have been brought to the site about 30 years ago - has been targeted by arsonists before, the most recent being six weeks ago.
Papakura Mayor Calum Penrose believed the fire was started with a bird's nest by children.
In response, security had been tightened with extra patrols and locked gates.
"It's a pain when these things happen but there are a lot of spirited people in the community keen to get it repaired and move on."
The Athletic Club had only minor smoke and water damage. Mr Penrose promised the grandstand would be repaired quickly.
"The police and Fire Service are doing their investigations so hopefully we'll know soon what caused the fire."
The stand was still in use yesterday, as people watched a police rugby match but the fire-damaged areas were roped off. Mr Penrose said if it hadn't been for firefighters' quick response the whole complex would have been gutted. About 44 staff and 12 fire engines were needed to battle the blaze.
Fire Safety Officer Michael McEnaney said the area of origin of the fire "leads us to believe it's a little bit suspicious".
He said it was a good save from the team in terms of containing the fire.
"I don't know about the facilities underneath and one side of the grandstand will need some work, but part of it is probably useable."
Police yesterday joined fire safety investigators at the scene.
