"The disappointing thing is, by the time we make it more secure it will be nearly $1000, by the time we pay for our excess and more padlocks . . . the income we generate from our stores simply goes back to the community so the community is going to lose out."
The site had extensive lawns which took several hours to mow, even with the ride-on.
"It's just very inconvenient and it's not nice knowing that someone is snooping around. We've got kids there - not that they are there at night - but it's just the thought of people being there that shouldn't be."
The theft last weekend was the most serious one to occur during his time at the site, he said.
"This is obviously organised. We get the odd teenager mucking around but this is a bit more planned."
The green and yellow LA105 model ride-on was traceable by its serial number and could be recognised if taken in for servicing, Mr Bishop said.
"If you are offered a cheap mower there's a reason why it's cheap. If it looks too good to be true it probably is."
It is the second mower theft in the district in a week, with the Wairarapa A&P Society's ride-on mower also stolen from a locked shed at Clareville Showgrounds. Senior Sergeant Mike Sutton, of Masterton police, said there were no indications the thefts were linked.
"It could indicate that they might be sought after at the moment and it's a reminder to keep your property secure and sheds locked up."
It was likely the thieves would have needed a trailer to transport the mower, so it was possible someone may have seen something, Mr Sutton said.
Anyone with information was asked to contact Masterton police on (06) 370 0378.
