South Korea's President Moon Jae-in and US President Donald Trump have agreed to exert stronger pressure through sanctions on North Korea following its nuclear and missile tests.

South Korea's presidential office said the two leaders came to an agreement following a telephone call today.

"The two leaders agreed to strengthen cooperation, and exert stronger and practical sanctions on North Korea so that it realises provocative actions leads to further diplomatic isolation and economic pressure," Blue House spokesman Park Soo-hyun said in a briefing.

The Blue House said Mr Moon and Mr Trump had strongly condemned the latest missile launch by North Korea, and agreed that the two nations would work with the international community to implement the latest UN Security Council's resolution 2375, Mr Park said.

It comes a day after North Korea said it is seeking an "equilibrium" of military force with the United States, according to the rogue state's official KCNA news agency.

The North's leader Kim Jong-Un said the country was close to the goal of completing their nuclear force and should use all state power to finish as they have "nearly reached the terminal".

"Our final goal is to establish the equilibrium of real force with the US and make the US rulers dare not talk about military option for the DPRK," Kim Jong-Un said, according to the KCNA report.