Authorities are closely monitoring a large crack that has developed in a parcel of land near Paddy's Path, a walking track between Wye River and Separation Creek.

About 211 tonnes of earth - 600 cubic metres, or the equivalent of about 180 truckloads - could come crashing down the hillside.

Emergency services are assessing whether nearby homes would be affected if this happened.

Roads through the immediate area, which was affected by the 2015 Christmas bushfires, have been closed to vehicles and pedestrians.

More than 150 rock falls and landslides have occurred along the Great Ocean Road since heavy rain set in about three weeks ago.

Part of the Great Ocean Road between Lorne and Wye River remains closed due to erosion.

There is local access from Skenes Creek to Wye River, but no trucks or buses are permitted access. Motorists can access Lorne via Deans Marsh-Lorne Road, and Princes Highway is another alternative route.

Meanwhile, already flooded parts of Victoria are set to receive another hammering on Tuesday night.

Melbourne will not see the rain until Wednesday, when between 10 to 20 millimetres is predicted to fall.

"Thursday will see a significant drying out as that system moves east of the state," Weatherzone senior meteorologist Brett Dutschke said

"But there is potential for significant flooding over Gippsland from Wednesday night and into Thursday, though that should ease as we head into the weekend."

Heavy rain which could cause flash flooding is expected to hit north-west Victoria by Tuesday afternoon.

Up to 70 millimetres of rain is expected in some parts.

A low pressure system travelling east from South Australia will bring the fresh band of rain, extending to the Mallee and the Wimmera districts by the evening.

By midnight, parts of the south-west, Northern Country and North Central districts could be soaked. The rain is expected to reach the central district by early Wednesday.

The Bureau of Meteorology issued a severe weather warning for heavy rainfall just before 5am on Tuesday.

Affected locations could include Mildura, Horsham, Bendigo, Shepparton, Seymour, Maryborough and Ballarat.

Victoria's Emergency Management Commissioner, Craig Lapsley, warned that Victorian rivers were already full.

"We need to be mindful there is more water coming," he said.

"Every drop of rain that falls from the sky is going to be in the river system and has the potential to increase flooding at the local level."

Elsewhere in the state, there are fears for towns such as Charlton, which narrowly escaped major flooding at the weekend.

But a State Emergency Services spokeswoman said there was more concern for towns where creeks and rivers were expected to reach peak levels.

"The focus areas today are predominantly Quambatook, Culgoa, Serpentine, Bears Lagoon, Durham Ox, Appin South and Kerang," she said.

"They're the ones with peak levels which are expected to be reached today."

An elderly farmer died in floodwater last week and there have been several rescues in recent days.

Major flood warnings remain for the Avoca and Wimmera rivers, with moderate warnings for the Loddon, Ovens and King rivers and several minor and flood watches for other catchments in the state.

The SES suggests flood-affected residents keep clear of creeks and storm drains and be aware of the potential of landslides or debris across roads.

With Aisha Dow