South Korea's finance minister said Friday that Seoul will make internal preparations to carry out economic projects with North Korea when the conditions are right.

Hong Nam-ki, the minister of economy and finance, was in the U.S. capital to attend a meeting of the Group of 20 finance ministers and central bank governors.

Speaking to reporters on the margins, Hong said he believes Thursday's summit in Washington between South Korean President Moon Jae-in and U.S. President Donald Trump created momentum to restart nuclear disarmament talks with North Korea.

Moon's push to expand economic cooperation with the North has been largely obstructed by the deadlock in denuclearization negotiations between Washington and Pyongyang.

"I don't think inter-Korean economic cooperation can begin in earnest immediately, but we will make preparations internally and quietly with other relevant ministries," Hong said.

"In order for inter-Korean economic cooperation to begin in earnest, I believe there needs to be an easing or removal of sanctions on the North," he added.

North Korea has been under tough international sanctions for its development of nuclear weapons and ballistic missiles.

In his two summits with Trump since last year, North Korean leader Kim Jong-un has sought to get sanctions relief in exchange for a commitment to dismantle the nuclear and missile programs.

At the start of his meeting with Moon on Thursday, Trump made clear that he wants the sanctions to stay on short of a "big deal"

on dismantling all of the North's weapons of mass destruction facilities.

But he also expressed an openness to "smaller deals" and allowing the reopening of an inter-Korean industrial complex in the North and the resumption of tourism to the country's Mount Kumgang at the right time.

Hong declined to elaborate when asked what preparations are under way, saying they will be announced under the right conditions, given their impact on other countries.

Earlier in the day, Hong met with IMF chief Christine Lagarde and called for the IMF's active support in case progress is made in North Korea's denuclearization and sanctions relief and inter-Korean cooperation gets under way.

Hong made a similar appeal for assistance for North Korea during a separate meeting with World Bank President David Malpass.

Hong and his Chinese counterpart, Liu Kun, agreed to strengthen policy coordination between the two neighbors through close communication, according to the Ministry of Economy and Finance.

On Saturday, the minister plans to meet with U.S. Treasury Secretary Steven Mnuchin to seek Washington's cooperation on potential U.S. tariffs on South Korean auto imports and extending a U.S. waiver for South Korean imports of Iranian oil.

"Our government is reviewing alternatives to Iranian oil imports, but it's not an easy situation," Hong said. "The negotiations are still under way, so let's wait and see."

The U.S. granted temporary waivers to eight countries, including South Korea, in November to allow them to continue imports of Iranian oil at sharply reduced volumes following Washington's reimposition of sanctions on Tehran.

The waivers are set to expire May 3. (Yonhap)