While the panel was at work, Mr. Moon suspended the construction of the two reactors, both inside the Gori nuclear power complex in Ulsan, in the southeast of South Korea.
On Friday, after three months of study, the panel endorsed a return to construction. Three-fifths of the panel supported the projects, while the remaining members were opposed.
Mr. Moon’s office said it would honor the recommendation.
Some villagers opposed to nuclear power who had gathered in front of a government building on Friday cried when they heard the panel’s decision. Civic groups campaigning against nuclear energy later said they respected its recommendation. But they lamented the influence of pronuclear groups who have carried out extensive publicity campaigns in recent weeks, promoting the benefits of nuclear power and warning that a phaseout could damage the economy.
“After 40 years of nuclear power, special interest groups connected to the nuclear power industry have taken root everywhere in South Korean society, blinding the eyes of the people,” the Korean Federation for Environmental Movements said in a statement.
The panel’s advice appeared to give Mr. Moon political cover on a highly divisive issue, saving him from having to order the costly abandonment of the effort. The government-controlled Korea Hydro & Nuclear Power Company, the country’s sole nuclear operator, has already spent $1.4 billion on the construction of the last two reactors.
But the panel supported Mr. Moon’s long-term policy of weaning South Korea off nuclear energy, with 53 percent urging that nuclear power be scaled back, while nearly 10 percent wanted it expanded. More than a third favored maintaining current levels.
South Korea is the world’s fifth-largest nuclear energy producer, with 24 reactors providing one-third of its electricity needs.
The panel “recommends that the government make energy policy decisions in a direction of scaling down nuclear power generation,” said its chairman, Kim Ji-hyung, during a nationally televised news conference on Friday.
Besides the five plants under construction, South Korea had planned to build six more. Mr. Moon has scrapped those plans. His government has also vowed not to extend the operation of existing reactors when they reach their life expectancy.
In June, South Korea retired its oldest nuclear plant, Gori Reactor No. 1, which went into operation in 1978. Ten others will reach the end of their design life by 2030.
Mr. Moon’s conservative predecessors championed nuclear power as a cheap energy source that they said helped drive the country’s export-dependent manufacturing sector and kept consumer electricity bills low. They had also hoped to develop nuclear into an export industry in its own right. South Korea is building four reactors for the United Arab Emirates under a $20 billion contract.
But Mr. Moon has promised to invest more in renewable energy sources. He also said he would issue no new licenses for coal power plants.
Skepticism over nuclear energy has grown in South Korea in recent years.
Not long after the Fukushima disaster, South Koreans learned that nuclear plants across their country included parts whose safety test results had been faked. The country is also running out of space for high-level radioactive wastes, but no town has been willing to host a central depository. A 5.8 magnitude earthquake near some of the plants last year also raised concerns.