Park Jie-won, a former four-term lawmaker and close aide to late President Kim Dae-jung, began work as head of the country’s top intelligence agency Wednesday.

A day earlier, President Moon Jae-in appointed him to lead the National Intelligence Service shortly after ruling party lawmakers on the National Assembly Intelligence Committee adopted a confirmation hearing report in a session boycotted by members from the main opposition United Future Party.

During Monday’s confirmation hearing, an UFP lawmaker claimed that Park signed a secret deal with a North Korean official in the process of arranging for the first-ever inter-Korean summit in June 2000. As evidence of his claim, Rep. Joo Jo-young revealed what he said was a copy of the clandestine accord, dated April 8 that year, which committed South Korea to provide $2.5 billion in economic assistance to North Korea over three years after giving it $500 million on the occasion of the summit.

On the copied document is what is alleged to be the signature of Park, who acted at the time as a special presidential envoy to set up the summit between former President Kim and then North Korean leader Kim Jong-il.

In a statement issued Tuesday, Park said the document was “false and fabricated,” adding he would consider taking legal action against Joo, who serves as floor leader of the main opposition party.

Earlier in the day, Joo told a radio program that a reliable former ranking government official recently visited his office to hand over the document, asking him to bring up the issue of the clandestine deal at Park’s hearing.

The statement from Park demanded Joo disclose the identity of that former official.

The focus of the controversy, which could raise serious questions about Park’s qualification as NIS director, should be on confirming the authenticity of the document through thorough and objective scrutiny.

It might be presumed that if there actually existed a secret deal, Park could be placed in an inherently weak position in dealing with North Korea.

In 2003, Park was sentenced to three years in prison for his involvement in a South Korean business group’s illicit transfer of $500 million -- $450 million in cash and $50 million in kind -- to North Korea right before President Kim visited Pyongyang for the first inter-Korean summit.

If the document disclosed by the opposition legislator is proved to be authentic, it would affirm that the Kim Dae-jung administration had pledged to provide Pyongyang with far more financial rewards for agreeing to hold the first inter-Korean summit.

In his statement, Park quoted other members of the South Korean delegation that negotiated with the North to arrange for the 2000 summit as saying they have no memory of the document and that it is totally untrue.

But Park, who was given a special presidential amnesty in 2007, appears to have discredited his clarification by frequently changing his words.

When the document was disclosed at Monday’s confirmation hearing, Park said it was not a fact, adding that he had no memory of it. Later he claimed it was fabricated. During a closed-door session later in the day, Park admitted to holding discussions on the $3 billion assistance but stressed he had not actually signed any official agreement, according to an opposition party member on the parliamentary intelligence committee.

President Moon needs to clarify all facts regarding the controversy. His top security adviser Suh Hoon is well positioned to answer inquiries from Moon as he participated in the secret talks to set up the 2000 summit as a working-level NIS official.

It is unnatural and could further stoke suspicion if they keep silent on the escalating controversy.

If the document was forged as claimed by Park, it would also constitute a serious crime and an investigation should be launched into who was responsible.

If ruling party lawmakers believe in Park’s claim, they have no reason to object to the opposition party’s call for a parliamentary probe into the issue.

Meanwhile, the ongoing controversy should serve as an occasion to enhance transparency in inter-Korean negotiations. Former government officials involved in talks with Pyongyang say it tends to request an under-the-table deal aside from a publicized one and use it as a tool to put pressure on Seoul.

Efforts to improve inter-Korean ties need to be made based on global standards and domestic public consent as in dealing with other international relations.