Dong Yang, vice-president of leading automotive think thank China EV 100, said the dual-credit plan will push new energy vehicle sales this year to past 2019 tallies.

Dong said carmakers will produce such vehicles to meet the quota, but they will have little gross profit. It will take another two to three years for them to make money and ramp up production.

He suggested authorities clarify related policies as soon as possible, including whether such vehicles will be exempt of the purchase tax after 2020.

"Give (automakers) something they can expect," Dong said. "They need a stable policy and environment."

Wang Xiaoqiu, president of SAIC Motor, China's largest carmaker, called on authorities to offer more favorable policies in terms of license plates and road rights.

SAIC and GAC, the Chinese partner of Toyota and Honda, suggested collaboration to deal with difficulties in the market.

"The industry demands a lot of money and it takes a great deal of time," Wang said.

"It also requires technologies from companies in different sectors. It will be hard for any carmaker who plays solo to stand out."

CATL, China's largest battery maker, is building a plant in Germany to serve local carmakers.

BYD Chairman Wang Chuanfu said the company has developed a new type of batteries with an energy density 1.5 times stronger than conventional batteries. Wang said the first vehicle sporting the new batteries will hit the market in June, and have a driving range of 600 km.

Chen Qingtai, president of China EV 100, expects electric vehicles to have better total ownership cost than gasoline cars by 2025.