Hastings SES controller Barry Cotterell said the unit received about 50 calls on Tuesday, mainly from Mornington and Somerville.

Some areas received up to 100millimetres of rain but the southern peninsula missed out.

"At the intersection of Main and Barkly streets in Mornington about 3.45pm, the cover of a concrete stormwater drain lifted with the force of the water under it," Mr Cotterell said.

A police car had to be parked on top of the cover to keep it in place.

Almost all the calls related to water streaming in from the ceilings of homes and businesses as gutters overflowed.

Frankston SES controller Brian McMannis said parts of Frankston and Mt Eliza became waterlogged.

"There were about 215 calls, mainly relating to house damage in Mt Eliza and Franksto. We had a few ceilings collapse in both suburbs because of the amount of water that got into the roofs."

The Mail photographer Gary Sissons was on the spot to capture the traffic chaos in Frankston resulting from the massive downpour, which also caused blackouts and flash flooding.

Many rail commuters, who had parked in Cranbourne Road, returned to find their cars flooded.

Mr McMannis said Mt Eliza was worst hit, closely followed by Frankston.

"There hasn't been heavy rain like this for a few years."

The storm ironically struck at the start of the Victorian SES's StormSafe Week, a campaign to raise community awareness of the need to be adequately prepared for storms.

Mr McMannis said the deluge underlined the StormSafe message for residents to clean gutters, downpipes and drains and ensure they weren't blocked, trim overhanging branches, make sure roofs were in good repair and tidy yards and verandas to ensure unsecured items didn't become potential missiles.