What started as a frightening mystery for a Sydney dog owner ended in cheers after a missing dog was found stranded on a narrow ledge nearly 13 stories above the ground.

Elbie, a two-year-old Jack Russell, disappeared after slipping through a tight gap on a balcony at an apartment building in Dee Why on Sydney’s Northern Beaches.

At first, her family did not know what had happened.

“We looked around the entire apartment and looked everywhere, every small, little spot, and there was nothing,” family friend James Tomac said to 9 News Australia. “We started thinking the worst possible thing, maybe she fell off the balcony.”

After searches and social media posts asking for help, a neighbour flying a drone near the building spotted Elbie trapped on a ledge on the far side of the high-rise.

The dog had survived for two days without food or water.

Firefighters then arrived to carry out the rescue as residents and onlookers gathered below. Firefighter Joel Spillane scaled the building using vertical rescue equipment while a tarp was placed underneath in case Elbie slipped.

“He was a little bit stuck, it took me a while to get him out,” Spillane said. “He was stuck in between the awning up there, but he was calm which helped a lot.”

For nearly 20 minutes, Spillane worked to free the dog before lifting Elbie through an apartment window to safety. The crowd below cheered as soon as she was rescued.

“We got him inside, he’s drunk heaps of water, they gave him a shower, and I’m sure he’ll be off to the vet,” Spillane said.

Elbie was later reunited with her owner, Jake Dobrin, who said he feared he might never see his dog again.

“I was over the moon,” Dobrin said. “I didn’t know if I was going to see her again, so very happy.”

Read more from 9 News Australia.