While on the campaign trail, Moon promised to renegotiate the comfort women deal, but also to "normalize" Korea-Japan relations severed by feuds over historical issues.
Since the inauguration of the administration of South Korean President Moon Jae In in May a year ago, the Japanese government has been urging South Korea to steadily implement the accord.
"Amid efforts to address threats from North Korea, this agreement should be a crucial foundation for cooperation between Japan and South Korea... for building a forward-looking bilateral relationship", he told reporters.
Under the 2015 accord, Japan apologized and promised to pay $8.8 million for care for survivors.
However, after Japanese Foreign Minister Taro Kono warned Seoul late December against trying to alter a deal originally celebrated as "irreversible", his South Korean counterpart Kang Kyung-hwa clarified the situation on Tuesday. Kono said he planned to "protest" the matter with Seoul.
Kang said that even though the deal was flawed, South Korea was not seeking to change it.
"It can not be denied that the 2015 deal was an official agreement reached between the governments of each country, and our government will not demand renegotiation", Kang said in a prepared statement.More news: Walmart Gives Worker Bonuses, Boosts Minimum Wage to $11
Suga said both countries have already committed to steadily implementing the deal and that both sides agreed the deal would settle the issue "finally and irreversibly".
"There is no room for any compromise on that agreement", he said.
The issue of women forced into sexual slavery for Japanese troops in the second world war has roiled relations between the neighbours - both of them USA allies and both threatened by nuclear-armed North Korea - for decades. Tens of thousands and possibly hundreds of thousands of women were compelled to work in brothels that served the Japanese military.
Numerous women forced into sex slavery by the Japanese aggressors came from the Korean Peninsula as well as from other parts of Asia, including China. Since then, similar statues have been placed in other cities, including San Francisco and Hong Kong.
Those opposed to the 2015 deal want Japan to take legal responsibility and provide due compensation.
The steady implementation of this agreement is both countries' duty to the worldwide community, Kono said following South Korea announcing its policy position.
"I seriously doubt that having a dialogue on Olympic participation alone will lead to any positive development on the issues of Japanese nationals abducted (by North Korea) or the nuclear and missile development".