Seoul: North Korea's Foreign Minister has said the country may test a hydrogen bomb in the Pacific, South Korean media has reported.

North Korean Foreign Minister Ri Yong-ho said he believed the North could consider a hydrogen bomb test on the Pacific Ocean of an unprecedented scale, South Korea's Yonhap news agency reported.

Ri was speaking to reporters in New York when he was asked what North Korean leader Kim Jong-un had meant when he threatened in an earlier statement the "highest level of hard-line countermeasure in history" against the United States.

North Korea could consider a hydrogen bomb test, Ri said, although he did not know Kim's exact thoughts, Yonhap reported.