The long-awaited stimulus plan for new energy vehicles is slated to come out by the end of May, which will boost domestic production of energy-efficient vehicles, said analysts.

On Wednesday, the State Council, China's cabinet, urged relevant departments to launch implementation details of the incentive plan for new energy vehicles by the end of May.

Miao Wei, vice-minister of the industry and information technology had earlier noted the plan would be launched in March.

Details of the final plan are still under study at the Ministry of Finance, said Zhen Zijian, deputy director of 863 Project for energy-saving and new energy vehicles under the Ministry of Science and Technology.

The plan was drawn up in cooperation with the three ministries.

Industry insiders said the incentives for new energy vehicles would be very similar to last year's pilot project for public sector buyers - all electric car buyers in certain selected cities could obtain incentives of up to 60,000 yuan.

"Conventional vehicles with fuel-saving technologies and hybrid vehicles will provide the short-term solution, while pure electric cars will supply the mid-term solution and fuel-cell vehicles will be the long-term solution," Zhen told China Daily on Thursday.

Analysts said many hybrid cars have rolled off domestic assembly lines over the past few years, and production will be accelerated after costs are offset by the incentives.

Zhen said small electric cars for short-distance travel may have offer good prospects for incentive qualification.

Ouyang Minggao, director of the National Laboratory of Automotive Safety and Energy echoed that view.

"Commercialization of eligible mid- and large-sized electric vehicles is not realistic due to battery restrictions and excess costs. However, small, all electric cars weighing less than 1,000 kilos have great growth potential," Ouyang said.

Given the varying production capabilities of Chinese automakers, the plan should take all parties' interests into account and apply to both hybrid and electric cars, said Duan Chengwu, a Shanghai-based analyst with IHS Global Insight.

The planned policy change has prompted analyst concerns over the lack of technical standards for new energy vehicles and charging stations.

The lack of common standards will lead to costly duplications in product and infrastructure development, said Duan.

A host of electric vehicle standards such as the plug used for recharging and other hardware and software systems are being reviewed by relevant research institutions and automakers, said a researcher with the National Laboratory of Automotive Safety and Energy.

"The stimulus plan will spur on large-scale use of new energy vehicles and provide for experimentation in formulating standards," he said.

But to what extent the stimulus plan promotes new energy vehicles depends on the size of the plan and how long the policy will last, said analysts.

Until 2020, most Chinese will still be first-time buyers and may be unwilling to pay more to protect the environment, said Li Jun, director of the research and development center of China FAW Group Corporation.