A Gold Coast theme park is celebrating after the birth of two polar bear cubs.
Sea World marine scientist Trevor Long says the cubs' delivery last Wednesday to the park's 16-year-old female Liya is "critical" to the long-term survival of polar bears.
The twins are the third and fourth cubs to be born at the park's Polar Bear Shores exhibit since it opened in 2000.
Henry and another cub, which didn't survive, were born in 2013 to Liya, and Mr Long says the new arrivals continue to highlight the importance of the park's exhibit.
"There's not a lot of zoological facilities breeding polar bears in the world," Mr Long said.
"There's about 22,000-30,000 polar bears, they are listed as threatened, and that's very critical.
"That's due to climate change, we're seeing a much shorter winter and these bears are not being able to reach their full potential."
The new cubs are being cared for by their mother in a specially crafted den, with Sea World staff monitoring the trio remotely.
Mr Long says the first couple of weeks are crucial to the bear's survival and staff are "cautiously optimistic" at this stage.
Both bears were born blind and weighing approximately 600g, but like their half-brother Henry, are expected to weigh around 250kg by the time they are two-and-a-half.
If all goes well, Mr Long says both cubs will be moved to a public display sometime in September.
