As debate rages over whether Melbourne needs the 75 billion litres the project will deliver this year, the pipe could make its debut in public life as a bushfire-fighting tool, if testing this week goes to plan.

Victorian fire crews will be given inspection and training along the pipe on Friday, in a bid to ensure they are equipped to safely tap the series of hydrants that have been built along the pipe's 70 kilometres.

Despite being weeks away from supplying drinking water to Sugarloaf Reservoir, pipe project director Rod Clifford confirmed the pipe could be used to fight fires this weekend if the need arose.

''If commissioning tests go well this week, the Country Fire Authority may be able to access water after Friday,'' he said.

Some water is in the pipe at the moment as part of ongoing testing, enabling fire crews to access flows before the pumping of drinking water begins in earnest.

The Black Saturday bushfires burned directly over the top of the pipe route, and with its path through the Toolangi forest, the pipe passes close to some of Victoria's most fire-threatened towns.

Melbourne Water has promised that security will remain tight on the pipe despite the multiple water offtakes along its length.

Hydrants will be locked within cabinets and flow meters will measure the amount of water extracted from the pipe each year by fire crews.

The Brumby Government yesterday hit back hard after the Victorian Farmers Federation said taking water from northern Victoria when Melbourne's supply seemed secure would be ''the greatest betrayal'' a government had ever perpetrated against country people.

Water Minister Tim Holding said farmers were by far the biggest winners from the $2 billion scheme to upgrade irrigation channels in northern Victoria, yet were paying only a tiny proportion of the costs.