Japan is carrying out an "economic attack" against South Korea after deliberately dismissing diplomatic discussions with the country as well as arbitration by the US, Lee said.
South Korea has been on the list of nations entitled to simplified export control procedures since 2004, which cover a wide range of items, except for food, timber and other goods.
Although automakers are still assessing the main factors driving the declines last month, industry participants and analysts expect an intensifying boycott campaign to hurt demand further, as diplomatic tensions grow.
South Korean Prime Minister Lee Nak-yon on Sunday urged Japan to correct its "reckless and risky" decision to curb exports to the country, saying that the worldwide community is concerned about security in Northeast Asia after the latest developments.
In the first such meeting since Japan's removal of South Korea from its so-called whitelist of countries with preferential trade treatment, top officials from the ruling bloc plan to analyze the possible effects of the Japanese move.
"Showroom visits are declining while consumers are holding off on signing contracts", a Honda Korea official told Reuters, asking not to be identified because of the sensitivity of the matter. It also warned them to be careful in visiting places in the country that are associated with Japan.
On Monday, the South Korean government outlined plans to invest around $6.5bn (£5.3bn) to try to develop products and materials which it now buys from Japan.
South Korea plans to raise "self-sufficiency" for 100 key components, materials and equipment items used to make chips, displays, batteries, automobiles and other products, with a goal to stabilize supply over the next five years.
Japan's foreign ministry also advised its nationals not to get involved in any trouble by staying away from protest sites.