The surge in the number of West Australians accessing the state government's Hardship Utilities Grants Scheme could be just the tip of the iceberg, the opposition says.

New figures show the number of Synergy customers making use of the scheme has jumped almost 60 per cent in the year to June 30.

While the carbon tax has increased electricity prices by up to 9.13 per cent, WA Labor has been critical of power price hikes driven by other factors under the Barnett government, which maintains the rises were necessary to reflect the higher cost of producing and transmitting electricity.

But opposition spokeswoman for community services and seniors Sue Ellery said the increases were "too high and too fast".

"People are really feeling the pain now," Ms Ellery told reporters on Thursday.