Taronga Zoo has welcomed three baby echidnas — known as puggles — into the world as the first short-beaked echidnas born at the zoo in nearly 30 years.

The puggles hatched between August 16 and 30, and have recently opened their eyes and started to develop spikes.

They each have a different mother.

The youngest puggle was born to Pitpa, the last echidna born at Taronga in 1987.

"All three mothers are doing an amazing job and tending to their puggles as needed," keeper Suzie Lemon said.

Echidnas are one of only two Australian mammals that lay eggs and are very hard to breed in human care.

The Zoo is yet to name the three new arrivals. ( Supplied: Paul Fahy )

They hatch after 10 days and are carried around by their mothers in a pouch for up to two months.

They are put into a special nursery burrow once they start to develop spines, where the mother returns to feed it every three to six days.

"A great deal of mystery still surrounds this spiny species," Ms Lemon said.

"Echidnas are quite elusive in the wild, so it's hard to study their natural breeding behaviours."

Keepers are pleased with the three puggles' progress as well as their mothers.

They are yet to determine the sex of the puggles and give them names.