Hobart to mark 40th anniversary of fatal Tasman Bridge collapse

It is 40 years since a ship ran into a pylon of Hobart's Tasman Bridge, causing a span to collapse, killing 12 people.

Cars and their occupants were left dangling off the edge of the bridge after the bulk carrier the Lake Illawarra caused the disaster at about 9.30pm on January 5, 1975.

Seven people on board the boat and five motorists were killed.

City authorities will close the bridge to traffic for a short period today, dim its lights and hold a minute's silence to remember the tragedy.

The bridge was reopened in October 1977.