Lord Howe Island could soon be declared a rodent-free zone, as a controversial baiting program comes to an end.

Key points: The island will be monitored for two years before it can be declared completely rodent free

The island will be monitored for two years before it can be declared completely rodent free The baiting program was controversial among islanders, with some fearing it would kill native animals

The baiting program was controversial among islanders, with some fearing it would kill native animals Rat poison antidote Vitamin K1 was brought onto the island to treat humans, but it wasn't needed

The rodent eradication program (REP) started on the popular tourist island in June and involved cereal pellets laced with poison being placed inside 22,000 lockable traps around the island.

Inaccessible areas were targeted by aerial drops of the same bait.

At the time, it was estimated there were 150,000 rats and 210,000 mice on Lord Howe — some 1,000 rodents for each of the island's 350 residents.

Today, the last of the poisonous pellets will be placed into traps, marking the end of the baiting program.

The traps will soon be collected and taken away, which will take about a month.

"We are running exactly as planned," said Peter Adams, chief executive of Lord Howe Island's board.

"You get a rapid reduction in the number of rodents at first, and then you get a few little blips of activity, so that's exactly what's happened here.

Islanders were divided on whether the baiting program should go ahead. ( ABC News: Mridula Amin )

"Yes, we believe it will be a successful eradication," he told the ABC

The island will be monitored for two years, and if no rats or mice are spotted, the area will be declared a rodent-free zone.

"Let's say there was a pregnant female, or a breeding pair left somewhere out there, it would take some time before that becomes obvious," Mr Adams said.

"It's such a rugged and inaccessible island in many ways."

The baiting was deemed safe for humans, but as a precaution, residents were told not to consume local eggs, milk or the livers of fish.

Peter Adams says the program has been a success. ( ABC News: Mridula Amin )

A supply of the rat poison antidote, Vitamin K1, was also brought to the island, but Mr Adams said it wasn't needed.

"Not a symptom, not a concern at all, so while the hospital was ready with all the things they needed, there was absolutely no need for it," he said.

Bird deaths numbers low

There were also concerns two endemic species of bird, the Lord Howe Island woodhen and the currawong, might be particularly at risk of eating the bait.

The former is an endangered bird, which was nursed back from the brink of extinction on the island in the 1980s — only a few hundred exist.

Currawongs have now been released back into the wild. ( ABC News: Mridula Amin )

The species were taken into captivity while the REP took place — placed in cages and looked after by staff from Sydney's Taronga Zoo.

"We've made sure that any animal, any bird, that was found dead, has been autopsied and tested," Mr Adams said

"We've had way less deaths from non-target species than was expected, or in our permits, that's been really encouraging," he said.

"All of the currawongs have now been re-released back into the wild … the woodhens won't be released until all of the bait has been retrieved from the bait stations."

It is thought mice first appeared on Lord Howe Island around 1850, and the rats came later, after escaping from a sinking ship off the coast in 1918.

They've played a role in the extinction of several species of plants and animals.

The island continues to see some "blips" of rat activity. ( ABC News: Mridula Amin )

Despite that, the REP has been a controversial issue among islanders.

Some didn't want it to go ahead, fearing it would do more harm than good, killing native animals.

Tensions boiled over earlier in the year, when a fight took place between two locals.

"There'll always be skeptics but I think things have settled a lot, and people really do hope that it has been successful," Mr Adams said.