Promises of a better Bruce Highway costing billions of dollars have followed another flooding of the major road which isolated towns and sparked rescues.

The "catastrophic failure" of the Ollera Creek Bridge has cut a critical route to flooded communities who may now have to rely on helicopters to deliver supplies.

Some areas have seen up to 600mm of rain in just 24 hours, with forecasts predicting more heavy downpours in coming days

A section of the Ollera Creek Bridge, located north of Townsville, collapsed into floodwaters on Sunday afternoon, severing a crucial link on the Bruce Highway and disrupting supplies to communities further north.