Emmett O'Brien, 49, died on Friday when his car was swept from the bridge over King John Creek at Caboolture, north of Brisbane.

His 16-year-old son Keegan and step-daughter Tegan, 21, were also in the car but were pulled to safety.

The same bridge claimed the lives of Tamra McDonald, her five-year-old son Tyler and her father, Tony, 74.

A short way south in Burpengary, 75-year-old Robert Leong died when his car was swept away by flood waters on Morayfield Road.

A friend of Mr O'Brien said he couldn't count how many people would miss the Elimbah resident, who ran the Brisbane chapter of the American Motorcycle Club (BAMC).

As president he was heavily involved with the group's charity work, which included big fundraising efforts for Caboolture support organisation The Haven.

The Haven manager Gail Torrens described him as "fearless", "invincible" and "a hero to many people".

"I was devastated, absolutely devastated," she said.

"He would have been… people like him you imagine to live forever, be around a long time."

Last year the club sold $20,000 worth of tickets in a huge car raffle that helped the charity buy a two-house property in Morayfield with space for two families or up to seven single people.

At the time Mr O'Brien told Caboolture News it was a great feeling to see people moving into the new houses.

"It makes our efforts worthwhile and obviously we're doing it for The Haven because they're doing it for the people," he said.

"We've got no problem digging in and helping there.

"Our members are all very enthusiastic and want to be involved because we're getting results like that and without our members we couldn't have done it."

Working out of their home base at Caboolture's Big Fish Tavern, club members also raised money to fund a back to school day for disadvantaged kids in the area.

Last year they donated 95 gift packs including shoes, books and stationery and another 20 including iPads, along with hosting a family fun day at a Caboolture park.

As loved ones grieve and hundreds of families continue the clean-up on Monday, the Insurance Council of Australia declared the inundation a catastrophe, the fifth in Australia this year.

By 10am Monday more than 7500 claims had been lodged with providers for more than $26 million, mostly for water damage through leaking roofs.