A survey on the Web news portal www.ifeng.com found 64 percent of respondents believed the new rule will be difficult to implement because it is related to officials' interests.
Local government departments had halted approvals for requests for such vehicles and had started to work on new quotas under the new rules, Li said.
"The future reform of official vehicle use will introduce market mechanisms and monetization," Li said.
Premier Wen Jiabao said in the annual government work report on Saturday that expenditures on such vehicles will not increase in 2011 compared with a year ago.
Beijing's standing deputy mayor Ji Lin last week said the municipal government will release the number of vehicles for official use in the capital as early as at the end of this month.
Earlier this month, the Ministry of Finance had published a rule regulating the budgets for such vehicles.