THE lower house has paved the way for the Murray-Darling Basin to receive an extra 450 gigalitres of water for its ailing ecosystem.

The extra water will be acquired by improving water efficiency on farms and removing key river constraints, like bridges and weirs, that affect flow throughout the basin, the government says.

The bill passed yesterday but still needs to pass the Senate.

Once it does it will establish a "special account" for $1.77 billion in Commonwealth funds earmarked for acquiring the extra water.

It will be pumped into the river system over a decade, and comes on top of the 2750GL pledged for the environment in the final basin plan tabled this week.

Environment Minister Tony Burke said this historic water reform was 110 years overdue but finally the government had a plan for restoring the basin to health.

"Australians are sick of this one not being solved," he told the chamber.

He paid tribute to the work of the Murray-Darling Basin Authority's chair Craig Knowles, who was seated in the gallery.

Coalition MPs were less pleased, with Nationals MP Mark Coulton saying it was sad "the rights of a frog supersede the rights of an Australian farmer".

Mr Burke moved an amendment to remove the words "up to" 450GL from the legislation, angering coalition members who called it a "fig leaf" and "green payoff" at the expense of basin communities.

He promised the extra water would not be acquired through compulsory large-scale water buybacks, but the coalition demanded an iron-clad guarantee.

Independent MP Tony Windsor accused the coalition of running a fear campaign, and challenged them to to oppose the bill if they felt so strongly against it.

The coalition voted against the amendments but they were carried anyway.

The opposition's own amendments to cap future water buybacks were later quashed, but they swore to implement the changes if elected to government.

The Water Amendment (Water for the Environment Special Account) Bill 2012 will now be considered by the Senate.