Levees have been holding in Australia's southeast but authorities continue to eye floodwaters as they shift downstream.

Emergency workers pile sandbags on a bridge over the swollen Loddon River at Kerang, Australia, on Tuesday. (Rodney Dekker/SES/Associated Press)

Efforts to protect the towns of Warracknabeal and Kerang from floodwaters paid off, but the Victoria State Emergency Service (SES) has issued an evacuation alert for residents in the town of Dimboola, 40 kilometres away, where several homes have already flooded.

The surging Wimmera River is expected to peak about midnight in the town, and not recede for at least 24 hours.

"A lot of work's been done in Dimboola today in relation to preparation for the peak that will arrive there tonight," SES incident controller Ray Jasper said.

Peter Stanley, also from the SES, says checks have shown the Dimboola weir is under pressure and could fail.

"All the water behind that would just be like pulling a big plug out of the river everything would flow down," he said.

An emergency alert has been issued for the town, with up to 25 properties are under direct threat.

As waters continue to move downstream, the towns of Brim, Beulah and Jeparit could be swamped over coming days.

Levee holds

On Tuesday and into the night, volunteers with bobcats worked to shore up six kilometres of levees along the Yarriambiack Creek in Warracknabeal and lay down 42,000 sandbags.

Australian officials are eyeing floodwaters as they head downstream. (CBC)

"If it wasn't for this levee bank, there's a great section of the town here would be under at least a couple of feet of water," said local resident Jack Kranz.

Until floodwaters begins to recede, authorities and volunteers have to ensure the levees hold, shoring them up with extra dirt and sandbags.

In Kerang, on the Victorian-New South Wales border, the immediate threat is over as a levee there is also holding firm.

The swollen Loddon River has stopped rising in Kerang and is expected to remain steady for days.

Sixty-two towns and cities across the state have now felt the impact of the floods.

This latest flooding in Victoria follows weeks of massive flooding in northeastern Queensland, which left 30 people dead.

Volunteers sweep mud onto the street from a flood-damaged house after the Brisbane River receded in the suburb of Westend on Friday. (Tim Wimborne/Reuters)

One victim was a 13-year-old boy, who insisted that rescuers first save his younger brother when the family car was caught in raging waters. The boy was buried alongside his mother, who was also killed in the flash flood.

The government has said the Queensland floods could be the country's most expensive natural disaster ever, but has not yet released estimates of the costs. Some estimates already were at $5 billion before muddy brown waters swamped Brisbane last week.

With files from The Associated Press