Wellington New Zealand's conservation efforts have been praised after two species of the country's iconic kiwi bird were removed from an international red list of threatened animals.

The North Island brown kiwi and the rowi kiwi are now classed as vulnerable rather than endangered by the International Union for Conservation of Nature (IUCN).

"This means instead of being in serious trouble, these two types of kiwi are no longer at such a high risk of extinction," Kevin Hackwell, from the environmental group Forest & Bird, said.

The rowi population has increased from only 160 individuals in 1995 to 450 adults today, while the brown kiwi population was flourishing in protected areas.

A lot of the success can be contributed to Operation Nest Egg where conservationists rescued eggs from the forest and released them after they hatched and fledged safely.

"It helped to increase juvenile survival while we developed effective landscape- scale pest control techniques," explained Hackwell.

Kiwi and other flightless birds are threatened by predators such as dogs, stoats, rats and cats.

However, the report does not indicate that all is well with New Zealand's birdlife. A government report published earlier this year said that it was in a "desperate situation."

Approximately 80 per cent of 168 native bird species are in trouble, with some at risk of extinction.

Internationally, the IUCN report mostly highlighted grave threats to animals and plants due to loss of habitat and unsustainable farming and fisheries practices.

Some 91,523 out of nearly 1.9 million described species have been assessed for the Red List, of which 25,821 are threatened, 866 are extinct and 69 extinct in the wild. The IUCN describes 11,783 species as vulnerable, 8,455 as endangered and 5,583 critically endangered.

The group said the Irrawaddy dolphin and finless porpoise that roam coastlines of Southeast Asia are now designated as endangered, imperiled by entanglement in fishing nets and other human activities.