Forest and Bird is calling for a wider drop of 1080 this year, with the biggest 'megamast' in nearly half a century expected.
Beech forests are expected to have their heaviest seeding season in 45 years thanks to climate change, which is welcome news for pests.
"First of all you get an explosion of rat numbers then an explosion of stoat numbers; then when the fruit and the seeds dry up, those two predators then turn their sights on our native birds," said Forest and Bird chief executive Kevin Hague.
A 'mast' year is when trees produce an "extremely heavy flowering and seeding", according to Forest and Bird.
"Historically this would trigger an abundance of food for native wildlife to make up for lean years. But now mast events boost rodent numbers, and in turn stoat numbers."
A 'megamast' is when podocarp forests join the heavy seeding at the same time.
Forest and Bird says mast years happen when the average summer temperature is more than 1degC above the average of the previous summer. This is the first time in 45 years 90 percent of the country's beech forests meet that threshold.
Hague wants the Government to put in an extra $20 million into the Department of Conservation's (DoC) predator control budget to fight the pest tsunami that's on the way.
"What we need to be doing is using 1080 right across much larger areas. That is actually is the way that we might be able to hold the line."
Hague says without it, years of pest control could be reversed.
"DoC currently doesn't have enough funding to protect even the top-priority list of sites in the face of this sort of event."
DoC got $20 million extra funding in 2014 and 2016 thanks to mast events. Last year's Budget put in an extra $20 million each year for four years, but even that won't be enough to successfully ward off a 'megamast', says Hague.
In past years, heavy seeding wiped out some native species, Hague said, including the only known population of mohua outside of Canterbury.
"DoC deployed its best practice ground-based trapping regime to protect these mohua, but they were overwhelmed by the plague of rats and stoats following that year's mast event.
"If DoC doesn't receive extra funding to increase its capacity to respond, we will see more of these localised extinctions."