Crews with heavy equipment on Sunday began the demolition of a Florida home over a huge sinkhole where a man is presumed dead after being swallowed by the earth three days ago.

The search for Jeff Bush, 37, was called off Saturday, and a heavy machine with a large bucket scoop was moved into position Sunday on what was believed to be solid ground.

The six-metre-wide opening of the sinkhole was almost covered by the house, and rescuers said there were no signs of life since the hole opened Thursday night.

Jeremy Bush, the man who tried to save his brother, was escorted with a woman by a deputy to the front of the house early Sunday before equipment moved into position. He repositioned some flowers from a makeshift memorial to a safer location, where Bush and the unidentified women knelt in prayer.

Jeremy Bush jumped into the sinkhole to try and save his brother Jeffrey, who is presumed dead. (Chris O'Meara/Associated Perss)

People gathered on lawn chairs, bundled up with blankets against unusually chilly weather. Several dozen milled about within view, including officials and reporters.

Hillsborough County Administrator Mike Merrill said officials had talked to Bush family Sunday. Crews would try their best to move the structure forward, toward the street, so the family can get some belongings, Merrill said.

"We don't know, in fact, whether it will collapse or whether it will hold up," he said.

He said crews' goal for Sunday is to knock down the house, and on Monday they will clear the debris as much as possible to allow officials and engineers to see the sinkhole in the open.

Demolition paused Sunday later morning as firefighters just outside the home went through belongings found inside, putting items such as books, binders and what looked like photo albums into boxes. They gestured to the Bush family, positioned across the street, as they sorted the items.

The Rev. John Martin Bell of Shoals Baptist Church said he had been with the Bush family all morning. "We just prayed with them," he said, adding that the family hopes to salvage keepsakes such as photographs.

Bell said all five who lived in the house — Jeremy Bush, 35; his girlfriend, Rachel Wicker, 27; their daughter, Hannah, 2; and two others ages 50 and 45 — were in need of support and prayers from the community.

Jeff Bush was in his bedroom Thursday night in Seffner — a suburb of 8,000 people 15 miles east of downtown Tampa — when the ground opened and took him and everything else in his room. Five others in the house escape unharmed as the earth crumbled.

The Hillsborough County Sheriff's Office is conducting the investigation.

Detective Larry McKinnon said that sheriff's office and the county medical examiner cannot declare Bush dead if his body is still missing. Under Florida law, Bush's family must petition a court to declare him deceased.

"Based on the circumstances, he's presumed dead, however the official death certificate can only be issued by a judge and the family has to petition the court," McKinnon said.