A new species of bird with a distinctive orange-red coloured tuft of feathers on its head has been found in Cambodia's populous capital city, conservationists said on Wednesday.

The remarkable discovery of the Cambodian tailorbird, or orthotomus chaktomuk, in Phnom Penh -- and several other locations including a construction site just outside of the city of 1.5 million people -- has astounded conservationists.

"The modern discovery of an undescribed bird species within the limits of a large populous city... is extraordinary," Simon Mahood of the Wildlife Conversation Society told AFP.

The small bird, which has a black-feathered throat and is the size of the more common wren, lives in thick, lowland scrub in Phnom Penh and other sites in the nearby floodplain, which the WCS said had kept it concealed for so long.

Known for its distinct plumage and a loud call, the bird was discovered by scientists from conservation groups, including WCS and BirdLife International.

The bird was named after a Phnom Penh riverfront area "chaktomuk" -- the conjunction of three rivers -- where it was found, the (WCS) said in a statement.

"The discovery indicates that new species of birds may still be found in familiar and unexpected locations," Mahood added.

"The new bird teaches us that conservation of birds and other wildlife begins at home and that we can all play a part in protecting Cambodia's wildlife."

Mahood said scientists started the research on the bird in June last year explaining it is currently not a threatened species despite its habitat in the city of 1.5 million people.

But WCS recommended that the species is classified as "Near Threatened" under the Red List of the International Union for Conservation of Nature (IUCN) because the bird's "habitat is declining" due to agricultural and urban expansion.

Hong Chamnan, a Cambodian forestry official who has worked with the team, told AFP the discovery brought great "pride" to the country.

"I believe that we may have this new bird in other areas in the country," he added.

Steve Zack, WCS coordinator of bird conservation said more study was needed to understand "the distribution and ecology of this exciting newly described species to determine its conservation needs".