Banteng are a type of wild cattle native to Southeast Asia and listed as critically endangered on the International Union for Conservation of Nature's Red List of threatened species.

Their natural habitat is forests and grasslands, but only a few thousand remain in the wild and they are mostly threatened by hunting, logging and industry.

Cambodia has lost around 33 percent of its tree cover since 2000, according to Global Forest Watch, as the government allows firms to clear vast tracts of land -- including in protected zones.

Conservation groups Rising Phoenix and Siem Pang said that 16 banteng found in the wild were herded over three days last week through a "mass-capture funnel trap" onto a truck before being relocated to a wildlife sanctuary.

For the first time, a helicopter was used to guide them through the funnel.

The operation took place in Siem Pang in northeastern Cambodia.

The conservation groups said that the method "opens the way for further such operations to relocate Banteng trapped in isolated forest patches elsewhere in the country".

They added that the banteng will be monitored and protected at the Siem Pang Wildlife Sanctuary.