BBC News website environment correspondent
One wolf pack is to be shot (Image: WWF-Canon/Chris Martin Bahr)The Norwegian government has decided to kill five of the country's grey wolves - a quarter of the entire population.
It says the decision is necessary to protect domestic livestock, but one campaign group has condemned the cull.
WWF-Norway says two wolves have been shot already, one of them from a pack which has not been targeted and which it fears may now not manage to survive.
Wolves are protected in Norway, and are listed as critically endangered, and WWF says many people oppose the cull.
The decision to kill five animals out of the 20 remaining in Norway was taken by the nature directorate, which advises the government. WWF-Norway is calling for an immediate halt to the hunt.
Survival 'at risk'
Its head, Rasmus Hansson, said: "If the Norwegian environment minister does not stop this hunt, he will have the dubious honour of allowing the regular hunting of a nationally endangered species.
Breeding may be at risk (Image: WWF-Canon/Chris Martin Bahr)"The culling of 20-30% of a population this size is a serious threat to the survival of this species in Norway.
"This practice is contrary to internationally accepted standards for wildlife management. No other country that I know of has such an aggressive policy towards its wolves."
The Norwegian parliament decided last May the country should sustain at least three family packs of wolves.
Packs can range in size from two adults to 10 or more animals covering several generations. WWF says the current hunt will reduce the number of packs to two at most.
Mr Hansson told the BBC: "One wolf from the pack to be culled was shot on 15 January, and another female from a different pack on 21 January.
"We don't know the exact size of the targeted pack, because we don't know whether it produced any cubs last summer. If it did, they will be left orphaned.
"Now, in all likelihood, by killing the wrong animal they've ruined another pack. The animal was an alpha female, so breeding may be affected and the pack could dissolve."
Norway's wolves are now very rare (Image: WWF-Canon/Roger LeGuen)WWF says there were an estimated 50-80 wolves in the southern part of Norway and Sweden in 2001, consisting of several families.
That year Norway approved the culling of eight out of its 25 wolves, leaving 20 today, because the target was not met.
A recent study of the wider Scandinavian wolf population concluded there were 120 at the most.
Mr Hansson said: "There is a serious risk of genetic degradation in this population because of its small size. A genetically healthy population... should have at least 800 individuals."
He told the BBC: "The cull is meant to protect sheep. Sheep farming occupies 90% of Norway's territory.
"We have 250-300,000 moose and 30,000 reindeer. In that perspective 800 wolves shouldn't be too many, though we've never suggested it - it's just a biological fact."