Canterbury's regional council knew three weeks ago it could not release a much-anticipated rabbit virus this autumn.
Federated Farmers said it was disappointed by the setback. Farmers would have to rely on poisons yet again.
Its Otago president, Phill Hunt, said he spent about $15,000 a year controlling rabbits on his sheep and beef farm near Queenstown.
He said farmers were not happy.
"It's very disappointing, it seems to be a bit of bureaucratic nonsense. No-one has come up with a reason why it shouldn't be here.
"It seems to be taking time as pieces of paper get shuffled over people's desks."
The strain, from Korea and known as K5, was released in Australia a month ago. Otago farmers battling a plague of rabbits were promised it would be released in April.
ECan co-ordinated the application for the New Zealand Rabbit Coordination Group.
ECan biosecurity leader Graham Sullivan said the group was told to apply to three different authorities for approval.
Mr Sullivan said when the Environmental Protection Authority ruled the virus did not need its regulation last month, the group then had to apply to the Ministry for Primary Industries.
That process took 70 days. ECan learned this three weeks ago.
"It's a significant piece of work, comprehensive... and quite a few tests in it as well. Once we knew the detail we knew we weren't going to make our [release] date."
"We knew then that we weren't going to get there... yes."
Mr Sullivan said it took time to get the group together and then to inform the public.
"The project team are spread all around New Zealand and we get together every month or six weeks... so a meeting was brought forward... but it still took three weeks for us to get together, we've all got other activities we are involved with."
Farmers consider poison options
Mr Hunt said farmers were told it would be released this autumn.
"We knew there was going to be a hold up, but we weren't expecting the hold up to be quite as long."
Mr Hunt said his rabbit problem was costly. He hoped to avoid using poisons this year because of the new virus.
"It would save having to use some toxins like 1080, which we use every four to five years. We'll have to make a decision now whether we can hold off using those toxins and wait for the disease next year.
"Farmers can do individual control, but sometimes smaller pockets of land can get missed out and the disease isn't selective like that... it's a broad-brush approach that would lower the population of rabbits throughout the whole area affected."
Rabbits graze low and kill plants by taking the crown out of the bottom, leaving bare patches of land, Mr Hunt said.
"It's very hard to get grass established on those, which means the potential for erosion becomes higher."