As a result, the club may face a repair bill of thousands of dollars, which it will have to claim in insurance.
But club members will not let the vandals destroy their season, even though bowling activities will be curtailed this summer.
About a month ago, Mr Galvin noticed discolouration on the club's Bayfield Rd green.
The brownish tinge, with black patches where grass had died, had spread to cover about a third of the 1000sq m green.
The full extent of the damage was only likely to be revealed during the next few weeks.
It appeared bundles containing powdered slow-release herbicide had been thrown over a fence on to the green.
The club was waiting to see if the grass would regrow, Mr Galvin said.
He had laid activated carbon on the affected areas to neutralise the suspected herbicide in an attempt to minimise the damage and added fertiliser to prompt regrowth.
"We have had the New Zealand Turf Institute take away samples and put them in ideal growing conditions to see if it will grow back."
Bowls could still be played on part of the green, avoiding the damaged section, which would be out of action for at least several months.
The thought someone had willingly caused such damage was soul-destroying for the club's 100 members, some of whom had spent hours preparing the green, Mr Galvin said.
"We find it really quite disappointing because we are an active club in the community - we coach high school children and hold community bowls evenings and an annual kids' Christmas party."
It was unclear when the incident occurred, because it would have taken some time for the effects to show, but Mr Galvin believed the damage was done by older people.
"The act seems to have been well thought-out and deliberate. I don't think it was kids or even teenagers."
The Andersons Bay club had a full programme planned for the summer and Mr Galvin said members would play on.
Opening day is September 28.
