Flood levees are being put to the test as swollen rivers peak or approach their peak in the northern Victorian towns of Echuca and Kerang.
The Murray River surpassed the 1993 flood level of 94.77 metres above sea level at Echuca on Saturday and is forecast to peak around 95m on Sunday evening into Monday.
Twenty homes in and around Echuca Village were door-knocked on Saturday night after water seeped through a levee.
"Those levees, whilst they're holding at this point in time, do continue to be a vulnerability for that particular community," State Emergency Service Victoria's Tim Wiebusch told reporters on Sunday.
Engineers have checked the Victorian-NSW border town's three kilometre temporary dirt levee and it remains structurally sound.
"We can't always guarantee that they will hold in all types of scenarios and hence why we have an evacuation message out," Mr Wiebusch said.
The alert covers between 500 to 700 people living across 250 properties in the area. Some roads in Echuca have been closed but emergency services still have access for supply chains.
Further northwest, the Loddon River at Kerang has peaked below the 78m forecast at 77.97m but the threat is yet to pass.
Floodwaters have only slightly receded and aren't expected to noticeably drop for five to seven days, keeping the community isolated.
A levee in the southwest corner of the town has been breached, sending water into an industrial area, caravan parks and about 20 homes.
However most parts of Kerang remained dry at this stage, Mr Wiebusch said.
About 50 to 60 per cent of the 3000-strong local community have remained behind to protect their properties.
Premier Daniel Andrews has pleaded with residents in Echuca and Kerang to heed evacuation advice.
"Please give that very careful thought. We don't issue those warnings lightly," he said.
About 50 flood victims from across the state have taken refuge at the Mickleham quarantine centre, as more than 65 warnings remain active.
Meteorologist Michael Efron said a weather system is predicted to dump 15mm to 30mm of rainfall on parts of northern and western Victoria on Monday, before contracting on Tuesday and remaining mostly clear from Wednesday to Saturday.
But Mr Wiebusch said the Campaspe River at Rochester could return to moderate or major flood levels early next week, if upper-end rainfall predictions come to fruition.
"It could impact about 50 properties," he said.
Downstream from Echuca, the Murray River is expected to peak at major flood levels higher than 1993 and 2016 from Torrumbarry to Barmah on Wednesday and Thursday.
Major flooding isn't expected to hit Swan Hill until the first week of November.
The SES has received more than 8700 calls for help since the weather emergency began, including more than 750 for flood rescues.