Carmakers are promising to introduce more petrol-electric hybrid vehicles but the pace is not fast enough for US consumers who want better fuel economy as petrol prices rise, or environmentalists who complain the industry could do more to conserve resources, a Reuters report said.

Ford on Wednesday said it will add a second hybrid, powered by both a petrol engine and electric batteries, to its US model range in late 2006 or early 2007, the report added.

Ford officials at the New York Auto Show reportedly said the 2007 Mercury Mariner hybrid sport utility vehicle will build on the lessons learned from the Ford Escape hybrid SUV, which goes on sale later this summer, and Ford is also planning a hybrid midsize sedan beyond 2007.

But, despite what Ford described as “stepping up its commitment” to hybrids, a coalition of environmental and human rights groups singled out the second-largest US carmaker for not offering the fuel-saving technology across its vehicle range, Reuters noted.

The coalition, including the Sierra Club, reportedly said it planned to demonstrate outside the motor show on Saturday to inform the public that Ford and the industry could do more to cut emissions and the US dependence on oil imports.

“Ford has shown that they can make a 35 mpg SUV — now they need to use this technology throughout their fleet to clean up the environment and cut our oil dependence,” Dan Becker, director of the Sierra Club’s global warming and energy program, said in a statement cited by the news agency.

Reuters noted that, although US petrol prices have recently hit record highs, unadjusted for inflation, SUVs and large pickup trucks have been the fastest-growing segments of the market this year though JD Power and Associates reportedly said a survey of 7,126 consumers indicated demand for more fuel-efficient vehicles such as hybrids could grow if prices continue to steadily climb.

Reuters said that environmental groups have focused on Ford, in particular chief executive Bill Ford Jr., who was an outspoken advocate for the environment before he took over as CEO in 2001. Since then, the automaker has backed down on one of Bill Ford’s most noted environmental initiatives – to boost the fuel economy of Ford SUVs by 25% by next year, the report added.

The Escape hybrid, Ford’s first gas-electric vehicle, will be the most fuel-efficient SUV when it goes on sale this summer, Ford told Reuters, getting better fuel economy than most cars on the market, though the model has been delayed because its maker said it needed more time for testing.

The report said Toyota plans to launch two new hybrids this year, including an SUV while Honda has a hybrid Accord in the wings but the models take only a small fraction of overall US sales, which are expected to total 16.7 million vehicles this year.

“When you talk to SUV buyers, the number one dissatisfaction is fuel economy,” Dennis Clements, the group vice president and general manager of Lexus, told Reuters in an interview, adding: “So I think (the brand’s new RX400h SUV) will resonate. The luxury SUV business continues to grow, quite dramatically.”