The independent Zimbabwe Conservation Task Force said the 18-month-old elephants were being held in pens in the western Hwange National Park, along with pairs of most of the park's other animal species bound for North Korea. The country is a longtime ally of Zimbabwean President Robert Mugabe.
Johnny Rodgrigues, head of the task force, said elephant experts do not think the young elephants will survive the trip separated from their mothers.
No comment was immediately available from Zimbabwe's state parks and wildlife department.
Rodrigues, whose task force is an alliance of conservation groups, said all the animals — including zebra, giraffe and a range of antelope — were captured at the president's order to be given to North Korea. He cited witnesses and officials in the park.
Witnesses reported seeing capture and spotting teams, government vehicles towing cages and armed men at key watering holes with radios to call in the capture teams. The animals were being kept in quarantine in holding pens at Umtshibi camp in the park.
Rodrigues said officials in the department opposed to the captures leaked details to conservationists. They even reported some areas of the 5,500 square mile (14,000 square kilometer) Hwange National Park, the biggest in Zimbabwe, being closed to tourists and photographic safari groups.
"We fear a pair of endangered rhino in Hwange will also be included," Rodrigues said.
He said conservation groups were trying to find out from civil aviation authorities when the airlift will begin and were lobbying for support from international animal welfare groups to stop it.
Zoo conditions in North Korea, isolated by most world nations, did not meet international standards, he said.
Two rhino, a male known as Zimbo and a female called Zimba, given to the North Korean leader in the 1980s by Mugabe died only a few months after their relocation.
At the same time, other rhino given to the Belgrade zoo in the former Yugoslavia died after contracting foot rot in damp and snowy winter conditions there.
"This new exercise has to be stopped. People under orders to do it are too scared to speak out," said Rodrigues.
Opposition groups vowed to demonstrate against their presence. Troops loyal to Mugabe trained by North Koreans crushed an armed rebellion in the western Matabeleland province — where Hwange is located — and massacred tens of thousands of civilians in the 1980s.
The team's visit to Zimbabwe was in doubt. North Korea soccer officials refused to confirm their itinerary when they left Pyongyang for training in Switzerland on May 8.