Water customers will receive a �20 rebate on next year's bills

Julia Goldsworthy wants Minister Elliot Morley to copy the new scheme which will ensure people pay no more than 3% of their income on water rates.

Many South West pensioners say water rates will make up 10% of their income. The local water watchdog has backed the MP's call and said the initiative in Northern Ireland has set a precedent.

Why on earth should we have the highest water bills in the country as well? Julia Goldsworthy MP

Gillian Clifton, the regional manager of the Consumer Council for Water South West (CCWater South West) said the similarities between Northern Ireland and the South West were almost identical.

She told BBC News: "There is low population, low income and a huge coastline to look after."

The council said single pensioners on Pension Credit are currently paying about 7% of their disposable income on water charges, with many who are not on a water metre in a worse position.

The Northern Ireland initiative means that all taxpayers will subsidise the bills for about one-third of householders.

Julia Goldsworthy, the MP for Falmouth and Camborne, said there was no reason customers in the South West should be expected to pay more than everybody else.

"People on some of the lowest wages in the country are already struggling to pay for the unfair council tax and the high cost of housing", she said.

"Why on earth should we have the highest water bills in the country as well? I have written to the Environment Minister to demand that he looks again at water bills in the South West."

�20 rebate

In November, the Department for Environment Food and Rural Affairs (Defra) announced it was to carry out a pilot study in the South West to look at ways of making water more affordable.

The scheme will assess the effect of switching to water meters and whether people are getting all the benefits they need.

Defra said the initial phase of the study would take six months followed by a year of monitoring, with the first results expected in 2007.

Earlier this month South West Water said its customers were to be given a one-off �20 rebate on water bills for next year.