Melburnians are being urged to prepare for more wet conditions after slow-moving storms sparked flash flooding in the city's outer east late on Tuesday.

In some areas, up to 70 millimetres of rain fell in a short window, resulting in more than 400 calls for help to the State Emergency Service (SES) across the city.

The heaviest falls were in outer-eastern suburbs and some parts of the Dandenong Ranges.

The SES's Tim Wiebusch said the majority of the calls for help came from Croydon, Chirnside Park, Mooroolbark, Lilydale, Emerald and Olinda.

"Those 400 requests for assistance basically came within a 90-minute period," he said.

"Unfortunately, yet again, we saw people attempting to drive through floodwaters."

He said that meant 25 rescues took place that "could have been avoided".

"We just need people to make sure that if you come across floodwaters, turn around and find an alternate route," Mr Wiebusch said.

"Do not attempt to drive through floodwaters. It may be the last decision you make."

He said the Yarra Ranges Shire had set up a relief and recovery point at Mount Evelyn to support people whose homes had been affected by the flash flooding.

The residents of three homes had to be relocated due to the flooding effects.

Bureau of Meteorology senior meteorologist Michael Efron said the severe thunderstorms had brought 70mm of rain to Lilydale, with 40mm falling in just half an hour.

He said there were unconfirmed reports of more than 100mm of rain falling near Seville, a town north-east of the Dandenongs.

"That thunderstorm activity yesterday was very slow moving so it did mean that those totals were really significant," Mr Efron said.

"Today we're going to see further shower and thunderstorm activity across central and eastern parts of the state.

"But those storms will be moving a bit quicker than what we saw yesterday,"

He said, being faster moving, the storms were unlikely to lead to intense rainfall in particular areas.

Mr Efron said a fresh system which was forecast to cross into the state on Sunday would bring more rain to northern Victoria, which has been the most affected by devastating floods.

Clean-up continues as other areas remain under threat

Across the other side of Melbourne, in the city's inner-west, residents are still cleaning up after the Maribyrnong river burst its banks almost a fortnight ago.

Mr Wiebusch said "significant rainfall" in the Snowy River catchment across the border with NSW had triggered flood warnings in East Gippsland.

He said communities from Orbost through to Marlo were likely to be affected by flooding from this afternoon through to this evening.

Mr Wiebusch said along the Murray River, flooding was still occurring from the town of Barmah up to Echuca.

"Echuca remains steady at 94.95 metres and is likely to be at that, or around that level for the next two to three days," he said.

He said it was expected to remain above the major flood level for another week.

At Kerang, he said water levels had receded "ever so slightly", but '"renewed rises" were expected over the next 24 to 48 hours.

Meanwhile, the Victorian government has announced temporary housing to accommodate those left homeless by floods in Rochester, where most of the town was inundated.

Emergency Services Minister Jaclyn Symes said the government was working with local leaders to ensure people can stay close to their communities as they rebuild.

"What we will be developing is a temporary village it will consist of non-permanent structures from caravans in the early days to modular-type housing as we get advanced," she said.

She said Rochester residents should be able to move into the facility at the Elmore Events Centre by the end of the week.