O negative blood donors are falling sick with colds and influenza across the country, leaving just two days supply once hospitals have been stocked.

Victorian flu cases were 12 times higher last Friday* than at the same time in 2018, according to the state's health department data.

Reported flu cases around Bendigo have reached 389, nearly 70 per cent higher than all cases reported to the department in 2018.

This year's flu numbers are second only to the 488 recorded in 2017, when there were more cases reported than in the previous seven years combined.

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The Campaspe shire has had more reported cases than in 2017, with 192 compared to 187 two years ago. So has the Mount Alexander Shire, which has had 87, compared with 70.

The Loddon, Central Goldfields and Macedon Ranges shires have not reached figures seen in 2017, though they too have seen high numbers of cases.

The Australian Red Cross is hoping the worst of colds and influenza has come and that more regular donors can soon help with supply, Australian Red Cross spokeswoman Erin Lagoudakis said.

However, in 2017 the number of laboratory-confirmed cases peaked in September, according to the Victorian health department.

In 2018, the peak came in October.

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One in 10 Australians have O negative blood, which can be given to anyone in emergency situations.

While hospitals have enough stock, more blood is needed in case of sudden emergencies, Ms Lagoudakis said.

Blood donated at the Bendigo Red Cross offices will be sent to processing facilities including in Melbourne, where different components will be separated and sent to hospitals across the country, she said.

The service needs 5000 O negative donations in two weeks from Australians, Ms Lagoudakis said.

"If you are O negative, someone in your family could be too. We're asking people to talk to their family and encourage them to donate," she said.

* The department's latest influenza data is preliminary and subject to change

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