Four pups that belong to the smallest otter species in the world have been shown to the public for the first time at Perth Zoo.

The four new Asian small-clawed otter pups were born in December but made their public debut on Monday for their first medical check-up.

Vets weighed them, checked their gender, inserted microchips and vaccinated them.

The vets identified two females and two males ranging in size from 520g to 560g.

Asian otters are the smallest of the 13 otter species, weighing just 3.5kg when fully grown, and are found in India, southern China, Malaysia and Indonesia.

Perth Zoo chief executive Susan Hunt said the pups were part of an Australasian breeding program to help protect a species that is threatened in the wild.

The Perth Zoo otters have had 16 pups in the past two years and these latest pups are the third litter for parents Asia and Tuan.

Asian small-clawed otters are social animals that pair for life.

Males play an important role in rearing the pups including nest building, swimming lessons and supplying food.

Older siblings also care for new pups and two older sisters are currently helping rear the newborns.

The pups recently started swimming lessons and are being carried out of the nest box to the pool by the adults and then carried back inside, but they will soon start venturing out alone.

In the wild, the otters are threatened by human activities including habitat encroachment, aquatic pollution and the meat and fur trades.