Ms McDonald's father Greg was out on his regular walk around Lake Burley Griffin on Monday afternoon, when the 55-year-old collapsed after a suspected heart attack near the National Library.

Passersby and nearby cyclists who saw Mr McDonald collapse rushed to his aid, with a group of four people taking turns to administer CPR while an ambulance was called.

It was this quick thinking from total strangers that Ms McDonald said saved her father's life.

"He was so lucky that there were people there around him that knew CPR," Ms McDonald said.

"If those people weren't there, I don't know what would have happened. He could have died, but they got his heartbeat going again."

After being revived with CPR, Mr McDonald was rushed to Canberra Hospital, where he is recovering and undergoing tests.

Now Ms McDonald is wanting to find the group of strangers who saved her father's life to thank them for their act.

She said she tried using a call out on Facebook to identify the good Samaritans, but hasn't been able to find them.

"We just want to come together and be able to thank them for what they did and show appreciation," Ms McDonald said.

"We've just been touched that there are people out there whop were able to help someone they didn't even know.

"They saved a life and we're so thankful for them."

While her father is still in hospital, Ms McDonald said he was in good spirits.

"He's talking now, although he can't remember what happened when he collapsed. He's in good spirits but a lot of pain still," she said.

"He's cracking jokes. I think the first thing he said after he woke up was 'can I have a beer?'."

Do you know who the strangers are? Email: andrewbrown@canberratimes.com.au