The young emperor penguin which became stranded in New Zealand, 2,000 miles from Antarctica, was on an intravenous drip today.

The ailing bird was moved to Wellington Zoo yesterday and underwent two medical procedures to flush sand it mistook for snow from its throat and stomach.

The penguin appeared healthy when it was first spotted on picturesque Peka Peka Beach on North Island on Monday - the country's first sighting of the species in the wild in 44 years.

But it grew more lethargic as the days passed, falling weakly into the wet sand at times, and wildlife officials feared it would die if they did not intervene.

"It's not going to survive here on the beach if we left it here," said Peter Simpson, a programme manager for New Zealand's Department of Conservation. "There's too much public pressure. It's just out in the open."

The penguin had been eating occasional twigs of driftwood and lots of sand, which experts said it probably thought was the snow it normally consumes for hydration in Antarctica, and in temperatures far higher than the sub-freezing conditions it is used to.

Wellington Zoo staff said the bird was dehydrated and suffering from heat exhaustion.

"Today it was not moving very much and, perhaps as a consequence of eating the sand... it certainly has lost condition," said John Cockram, a penguin expert from Massey University, yesterday.

Zoo vet science manager Lisa Argilla said the bird's throat was flushed with water to try to clear the debris, but it still seemed blocked, so it underwent a more extensive stomach flush today.

However, that still did not clear out all the sand, so a third procedure is planned for Monday. The penguin remained on an intravenous drip today to combat dehydration.

For the 40-mile (65km) journey to the zoo, the 32in (81cm) penguin was lifted into a tub of ice and then on to the back of a truck. The weakened bird did not need to be sedated for the ride.

The tallest and largest species of penguin, the emperors' amazing journey to breeding grounds deep in the Antarctic was chronicled in the 2005 documentary March Of The Penguins, which highlighted their ability to survive - and breed - despite the region's brutal winter.

Estimated to be about 10 months old, the penguin was probably born during the last Antarctic winter and may have been searching for squid and krill when it got lost. Experts have not yet determined if it is male or female.

"He's a young bird that's out swimming and foraging and doing what he's supposed to do. He just made a wrong turn someplace," said Lauren DuBois, assistant curator of birds at SeaWorld in San Diego, which has the only colony of emperor penguins in North America. Thirty birds live there in a 25F (minus 4C) habitat which simulates Antarctica, with up to 5,000lb (2,270kg) of snow blown in every day.

About six months after hatching, Ms DuBois said, a young emperor will head out to sea and spend up to four years in the water without coming back to the rookery.

"The birds will travel quite far," she said, noting it is not unusual for them to be in the water near New Zealand. "What is unusual for this penguin is that he's come ashore and he's causing quite a stir," she said.

"Anything above 32 degrees (0C) and they will start getting stressed," she said.

The bird's future is uncertain. New Zealand has no zoo equipped for the long-term care of emperor penguins, which can grow up to 4ft (122 cm) high and weigh up to 90lb (34 kg). Ms DuBois said SeaWorld would be ready to step in and help if asked.

Ideally, the penguin will heal enough to eventually be released into the wild. But returning it to Antarctica is not feasible, at least for now. There is no transport to the continent in the harsh winter.

There is also concern about infection. The penguin may have caught a disease by swimming through warmer climes, and wildlife officials would not want to be responsible for introducing illness into the insulated Antarctic penguin colony, Mr Simpson said.

Often, sick birds require rehabilitation for a month or two before being released, Wellington Zoo spokeswoman Kate Baker said, adding that some creatures with severe injuries remain in captivity.

The penguin's rare foray north captured the public imagination, with school groups, sightseers and news crews coming to the beach to see it and photograph it from a distance.

Christine Wilton, who discovered the penguin while walking her dog, returned to the beach yesterday to say goodbye.

"I'm so pleased it's going to be looked after," she said. "He needed to get off the beach. He did stand up this morning, but you could tell that he wasn't happy."