AUGUSTA — Central Maine Power Co., which filed for a $55 million rate hike last week, “simply cannot justify a major price increase for electricity customers,” the state public advocate says.

Advocate Stephen G. Ward, who heads the executive branch agency that represents consumers in utility matters, announced this week his office would oppose CMP’s request, noting the company’s rates have increased by more than $150 million since July 1990.

Given the state’s economic troubles, Ward said the latest CMP rate hike proposal “could not come at a worse time.”

Ward said CMP “has an obligation to demonstrate to its ratepayers that it has taken all necessary steps to reduce overhead, trim payroll and new expenditures.”

“There is no reason why CMP should be able to avoid the cost-cutting which other Maine businesses have been forced to undertake,” Ward said.

In filing its request with the Maine Public Utilities Commission last week, CMP said it needed new revenue to offset rising operating costs and make up for declining electricity sales.

The company said it had taken a number of savings steps, including a $30 million reduction in its 1991 construction budget to lower its borrowing costs.

However, CMP Vice President David E. Marsh said the company was still taking in about $20 million less a year than anticipated by regulators.

Ward says it will be up to the PUC “to look very carefully — and critically” at CMP’s economic forecasts.

“The state’s economy is faltering and many Maine households can’t keep up with expenses,” the advocate said. “CMP shareholders can’t reasonably expect to have their earnings insulated from the worst recession in decades. The survival of many Maine jobs will depend on how the Public Utilities Commission deals with this request.”

The PUC has nine months to review such cases. The CMP rate hike request is the company’s third in three years.