"Japan, a perpetrator 100 years ago, is once again committing economic invasion of Korea", the civic groups said.
President Moon said the tensions with Tokyo will act as a "stimulant" for the South Korean economy, adding: "I would like to thank the government, businesses and the people for responding to Japan's trade retaliation with one heart". "A peace economy - where peaceful relations drive economic growth - only sounds good, and it's not clear what it is and how things will be actually done".
Japan tightened controls in July on exports to South Korea, escalating a row over wartime forced laborers and sparking a boycott by South Korean consumers of Japanese products and services, from cars, beer and pens to tours.
While foreign-branded cars make up a small portion of domestic auto sales in South Korea, the business community is concerned a consumer swing away from Japanese imports for political reasons could grow in other sectors, such as tourism and retail.
Protesters also urged for the abrogation of GSOMIA, Korea's military intelligence sharing pact with Japan signed in 2016, holding pickets reading "We condemn the Abe government, apologize for forced labor". The North has been demanding that Seoul turn away from Washington and restart inter-Korean economic projects held back by US -led sanctions against the North.
The nuclear-armed North Korea - which attacked its neighbour in 1950, triggering the Korean War - has always been infuriated by military exercises between the USA and the South, decrying them as rehearsals for invasion.
Seoul's presidential office said it was highly likely to be "a new type of short-range ballistic missile".
And on Friday, North Korea carried out its third weapons test in the space of eight days, firing what it called a new "large calibre multiple launch guided rocket system".
Choi Kang, a senior analyst at Seoul's Asan Institute for Policy Studies, said Moon's comments could create friction with Washington and also send a wrong message to North Korea, which may think that its brinkmanship is working and push further to increase pressure on Seoul.
But they have also pointed to an erosion of trust after South Korean court rulings previous year ordered Japanese firms to compensate wartime forced laborers, a matter Tokyo says was settled by a 1965 treaty normalizing bilateral ties. He said that may complicate Washington's efforts to maintain cooperation to deal with the North's nuclear threat and counter the regional influence of China.
A second summit in Hanoi in February broke up amid disagreement on sanctions relief and what the North might be willing to give up in return.
Earlier on Monday, South Korea's government announced plans to invest about 7.8 trillion won ($6.48 billion) in research and development for local materials, parts and equipment over the next seven years to help cut reliance on Japanese imports. The government will also financially support South Korean companies in mergers and acquisitions of foreign companies and expand tax benefits to lure more global investment, while easing labor and environmental regulations so that local companies can boost production, the country's trade ministry said.
Civic groups have been holding rallies every Saturday since last month, after Japan imposed toughened regulations on exports of three tech materials used by Korean tech companies.
