Melbourne Water recorded just 121millimetres of rain so far this year at Romsey, compared with 211millimetres for the same time last year.

Mt Macedon fared better, with 253millimetres recorded to July 3, compared with 260millimetres during the same period last year.

Bureau of Meteorology Victorian regional office climate services manager Harvey Stern confirmed it had been a record dry start to the year.

"The last time Melbourne's annual rainfall was above average was 1996," Dr Stern said.

"Over the 12 years of this drought, Melbourne has now missed out on 1.8metres of rain, representing three years of average rainfall. It is going to take many years of good rainfall to remove these deficiencies."

The dry start extends the drought that has affected much of south-eastern Australia since late 1996.

Romsey farmer Patrick Francis keeps rainfall records on his 50-hectare property, Moffitts, where he has run cattle since 1986.

He said just 114 millimetres of rain had fallen this year to June 30 compared to the previous recorded low for that period of 143 millimetres in 1998.

"Factually, it is the driest first six months we have had. Some of the farms just look devastated."

He said recent rain made little difference to most farms and three months of close to 100 millimetres in rainfall was needed.

"As soon as we start to get the warmer weather in October, the pastures will just dry out. The deficit is so great that the lack of replenishment means as soon as it warms up, the pastures will dry off and there will be very little growth through spring."

Mr Francis said the message to farmers was not to be too optimistic in terms of stock. "The chances of getting enough rain to produce enough feed is very low. We need to change the approach to livestock and put the emphasis on the pastures."

"Pasture first, livestock second. If you manage for pasture and not for livestock, we'll be able to get through the very dry years without much stress."