The Government introduced appropriation legislation to parliament last week calling for more money from forward estimates for its water for the future and home insulation programs.

The Opposition supported the move owing to long-held conventions against blocking supply, but there was significant disapproval voiced in the Lower House from rural MPs, particularly in relation to the Government's water buyback approach.

The Government called for the $650 million from budgets next year and the year after to finance the buybacks and make up for water not sold due to a moratorium on sales in NSW.

Nationals MP for the northern NSW electorate of Parkes, Mark Coulton, slammed the buyback as "one of the most ill-conceived and sinister schemes ever administered by this government".

"There are, of course, plenty of willing sellers. Rural Australia is in a pretty tight position at the moment," Mr Coulton said.

"Cash-strapped farmers are selling their water entitlements to make ends meet. It is certainly not something of their choosing and it is certainly not something they would do with a long-term view…it is something which they have had no choice in."

Mr Coulton criticised the Government for bringing forward funding for water buybacks and not water infrastructure spending.

He said the very day the money was called for in parliament, the Lachlan River in Western NSW ceased to flow.

Opposition spokesman for Agriculture, John Cobb, said the bill was "a further nail in the coffin of regional communities" and would entrench "a Rudd-made drought in basin communities".

"If the Rudd Government continues to buy the lifeblood of regional communities without increasing the productive capacity, without investing in the system, be it the transfer system or the on-farm system, there will not be two million people left in the Murray-Darling Basin," Mr Cobb said.

Minister for Water, Penny Wong, said the Government had bought 600 gigalitres of water as at October 30 this year.

"That’s come at a cost to taxpayers of close to a billion dollars," she said.

"This is a difficult problem and one we are working to remedy, but it certainly can’t be fixed overnight and it certainly can’t be fixed by assuming we are simply not going to allow any extraction whatsoever from the River Murray."