UPDATE: WATER from the controversial $750m north-south pipeline has started flowing into Melbourne's reservoirs.

Premier, John Brumby, and Water Minister, Tim Holding, turned on the pipeline at the Sugarloaf Reservoir this morning.

The pumps will push the first of at least 70,000 megalitres through the 70km pipeline from the Goulburn River to Melbourne's Sugarloaf Reservoir.

The pipeline's flows mark the end of a political era of opposition to a north-south pipeline that started in 1967 when former Victorian Premier Sir Henry Bolte promised "not a drop of water will cross the divide to meet the needs of Melbourne".

In contrast, Mr Brumby has weathered heavy opposition to the pipeline, ranging from protests on Parliament's steps to threats from the Plug the Pipe Group to invade his family's farm.

The Premier has repeatedly argued the project was a winner for northern Victoria because it meant a $903 million upgrade of the region's ageing irrigation infrastructure in return for 75,000 megalitres of water for Melbourne.

However, the pipeline battle has severely damaged the Government's credibility in northern Victoria and could cost it the lower house seat of Seymour at the November state election.

Despite the calls to abandon the project, Mr Brumby has stared down the pipeline opponents, including some of his own parliamentary colleagues, who have branded it a ``white elephant'' and ``act of betrayal'' against drought-stricken northern Victoria.

Mr Holding is set to try to sell the benefits of the pipeline's flows to Melbourne, flagging an easing of water restrictions on March 31.

He will point to the fact that Swan Hill, Mildura and Shepparton - in the heart of northern Victoria's irrigation district _ are enjoying the benefits of watering lawns and gardens on stage one water restrictions, while Melbourne's 3.8 million residents remain on stage 3a restrictions.

The Opposition has warned it will curb the pipeline's flows by blocking crucial government amendments to the Eildon-Goulburn bulk entitlement that allow Melbourne to divert northern Victorian water savings down the pipeline to Sugarloaf Reservoir.

However, the Government will still be able to divert at least 22,000 megalitres of water, not created from irrigation upgrades, down the pipeline.

The Coalition needs the support of the Greens and Democratic Labor Party in the upper house to block the government amendments.