Manitobans could be facing yet another electricity rate increase.

Manitoba Hydro is seeking a 3.5 per cent hike to take effect in April 2013, but consumer advocates are fighting the proposal at a Public Utilities Board hearing on Monday.

"We have to face the realities of our system. We have to provide [an] economic system that's reliable. And to do that, it certainly costs money," said Glenn Schneider, a spokesman for Manitoba Hydro.

Schneider said export sales have not been generating the revenue officials had expected.

The public utility was already granted a two per cent hike in April and another 2.5 per cent increase in September.

If the latest request is granted, Manitobans will be paying eight per cent more in just one year, officials with the Consumers' Association of Canada told the hearing.

Furthermore, Manitoba Hydro is forecasting annual increases of up to 3.95 per cent annually until 2021.

The consumers' association warned that Manitobans are already facing electricity rates above inflation rates.

Gloria Desorcy of the association's Manitoba branch says she's worried about the impact the increases could have on ratepayers, "and not just for this two-year period."

"We're also looking forward, and we're not seeing let-up," she said.

Manitoba Keewatinowi Okimakanak (MKO), an organization representing most First Nations in the province's north, is also opposed to the rate request.

It told the hearing that many First Nations customers are low income families that can't afford the increases.

The hearing will continue into next week with a decision expected by the Public Utilities Board in the new year.