The meeting marks the first of its kind since the Donald Trump administration's inauguration on Jan. 20.

"Since the Trump administration took office, it has been sending out a clearer stance on its policy about the North and the Korean Peninsula than during the Obama government. (I) expect that will be reconfirmed during the meeting," Yun told reporters.

The two held a telephone conversation earlier this month in which they affirmed their countries' commitment to strengthen the bilateral alliance under the Trump administration.

Tillerson also called the North's nuclear program and its continued military provocations an "immediate threat" both to the US and South Korea.

The meeting will be followed immediately by tripartite talks also including Japanese Foreign Minister Fumio Kishida.

The back-to-back meetings come amid heightened tensions surrounding the Korean Peninsula in the wake of the North's recent ballistic missile test Sunday.

They are likely to discuss their joint approach to the growing threat from North Korea, including the use of the so-called secondary boycott aimed at punishing third-country firms involved in transactions with the North.

They could also exchange views on the possible implications brought on by the murder of North Korean leader Kim Jong-un's half brother. Pyongyang is suspected of having been behind the killing.

Yun told reporters that the death demonstrates the nature of the North Korean regime and that diplomats attending the G-20 meeting will likely have a keen interest in what impact the murder could have on the diplomatic landscape surrounding the Korean Peninsula.

Meanwhile, Yun is to hold bilateral talks with Japanese Foreign Minister Kishida on Friday. He also plans to hold a meeting with his Chinese counterpart Wang Yi during his stay in Germany.

South Korea and Japan have seen their ties fray over Tokyo's repeated claims to its easternmost islets of Dokdo and a diplomatic row in Korea over a girl statue recently erected in front of the Japanese consulate in Korea.

Japan's ambassador was brought home over the statue that symbolizes its wartime sexual slavery of Korean woman.

South Korea also faces growing pressure from China to retract its decision to allow an advanced US anti-missile system to be installed on its soil. (Yonhap)