About a dozen rolls of sheet netting for a planned 1.4km stock exclusion fence were taken from the 315ha privately owned wetland during the past week, most likely Thursday or Friday, Mr Riley said.
''We've been planning and fundraising for it for the past 12 months. These things take a long time working for a charitable organisation. Every cent that paid for it was given to us,'' he said.
''It's taken a long time for us to get that money together, so it's pretty upsetting to then lose it.''
Mr Riley said the amount of material taken would have fitted in a ''very large trailer'' and not all of the fencing material had been taken. He said he believed the theft was planned and not the work of opportunists.
''It's not just a `passing by stuff in your pocket' kind of thing. A lot of work has gone into it.''
He said he hoped somebody had seen something and would contact the police.
Winter projects the Sinclair Wetlands Trust had planned, once the fencing was installed, including the planting of 4000 native plants in the area to be protected by the fence, were now in question.
Driving posts for the fence would go ahead, with a neighbouring farmer volunteering his time and equipment next week, Mr Riley said.
The work to be completed after the fence was installed was in part to be done by a contingent of 40 American student volunteers arriving this winter to take part in volunteer projects in the area.
New jobs would have to be planned and funded ahead of the group's arrival within the fortnight.
The work to be completed this winter had received support from Mahinerangi Environment Enhancement fund, Fish and Game Otago and the QEII National Trust.
The donation box was stolen from the property around Christmas. Mr Riley called this latest theft ''another slap in the face''.
''It sucks,'' he said.
''And I live on site. It's quite an unsettling feeling knowing that somebody's turned up, lurking around the place and taken stuff away with them.
''And we don't know if they plan to come back and get the rest, or if there's other stuff they've noticed while they were here. It's unnerving.''
