Miami-Dade Police on Tuesday formally identified Ingrid and Tzvi Ainsworth as victims of the Champlain Towers South building collapse in Surfside, Florida.

The former Sydney residents, aged 66 and 68, were found in the wreckage on Monday, taking the official death toll to 28.

Canadian-born Ingrid, known as Itty, had a gift for making people feel like they were "the one", close friend Tzippy Kastel said.

"She just had this huge, contagious love for life ... this amazing aura and an energy about her," Mrs Kastel told AAP.

"People were really drawn to her.

"From joyous to sad or to whatever it was, she was the one I would turn to."

Mrs Kastel, who lives in the Ainsworths' former home in Sydney, said it was beautiful to see how Tzvi treated his wife "like a queen".

After spending nearly 20 years living in Australia, the Ainsworths moved back to the US four years ago to be closer to some of their seven children and extended family.

A grandchild was born the week of the building's collapse.

"It's a huge family and because of the type of people they are, it's a community-wide tragedy," Mrs Kastel said.

In a blog post for Mother's Day 2020, daughter Chana Wasserman said her mother made friends with every person she met.

"Everyone was treated as equals. The guy at the laundromat... the high school kid working at Blockbuster, the seamstress, the lady doing her nails, a pigeon... the outcast, the misunderstood, the popular, the unpopular."

Itty also surpassed seeing the world through rose-coloured glasses.

"My mother sees the world through rainbow-coloured glasses with unicorns and dolphins diving in and out," Ms Wasserman said.

Rabbi Timchus Feldman, who knew Tsvi since he moved to Australia as a child, also paid tribute to the couple as "exemplary" people who lived their faith instead of preaching it.

"They focused on radiating love and happiness to everybody they came in contact with," he told AAP.

"He had a heart of gold... (and) she was like a burst of sunshine."

The way the couple died has brought "indescribable pain and anguish" to their family - particularly their children and Tzvi's elderly parents in Australia.

"The pain, the anguish, the wait - not knowing anything - is something that actually can drive you totally insane."

"And it's really such a tragedy for parents to have to bury children."

Another 117 people remain missing 11 days after the 12-storey residential building collapsed.

A search-and-rescue effort has continued almost around the clock, pausing only for bad weather, dangerous shifting of the rubble, and the demolition.

Roughly half of the condominium building came tumbling down early in the morning on June 24 and rescue workers were kept away from the unstable half that remained standing for their own safety.

Rescuers have now begun searching through fresh rubble after the last of the building was demolished, allowing crews to scour previously inaccessible places.

Four more victims - including the Ainsworths - have since been discovered, Miami-Dade police say, raising the death toll to 28 people.

No one has been found alive since the first hours after the collapse.

In a statement, the Department of Foreign Affairs and Trade said it is not aware of any Australian citizens who were in the building at the time of the collapse.

"We extend our condolences to the victims and families of the Surfside, Florida building collapse."

"DFAT is providing consular assistance to Australians whose non-Australian relatives were in the building at the time of the collapse."

Australian Associated Press