"We are disappointed that it came to this. We were under the impression that everything was running well," Mr Madden said.
Horizons donated 40 traps to the trust in 2015 to trap pest animals in the Foxton Beach area.
Legislation requires that live-capture traps be inspected daily and captured animals removed, cared for or killed without delay.
The trust has said it is looking at whether kill traps could replace the live-capture traps.
Mr Madden said the downside of kill traps was the possibility of killing pets, which is why live-capture traps were used in the first place.
The trust used volunteers to check the traps.
"Personal health challenges and the weather has meant that our unpaid volunteers were unable to maintain their programme but did not advise us," Trust chairman John Girling said in a Facebook post this week.
"This is not offered as an excuse and Wildlife Foxton Trust should have checked up on them to ensure that the traps were still being managed well."
The two-year-old trust's main stated aim is to build a wildlife tourism and education centre at a site on the banks of the Manawatu River Loop in Foxton.
The trust aspires to raise around $3 million to get the centre built and operational.
Its latest accounts show general accumulated funds of $12,000.
