The federal government says the four Canadians who may be affected by the deadly building collapse near Miami are from two different families.

Global Affairs Canada says they are in contact with the families after the seaside condominium tower collapsed Thursday.

More than 150 people are unaccounted for and at least nine are dead after the 12-storey Champlain Towers South collapsed in Surfside, just north of Miami.

The federal government has offered few other details about the Canadians, including whether they are still missing.

First responders are continuing their efforts to find survivors today.

Three years ago an engineering firm said the building needed major repairs to fix damaged concrete in columns, beams and walls.