A day after Pyongyang hinted at possible military action against its neighbour, South Korea’s Unification Ministry has called out North Korea for not honouring past agreements between the two countries.

The latest escalation of tension on the divided peninsula was sparked by defectors from the North who have been sending back propaganda and food.

Kim Yo-jong, Kim Jong-un’s sister and one of his closest aides, issued the veiled threat in a statement carried by state news agency KCNA on Saturday.

“By exercising my power authorised by the Supreme Leader, our Party and the state, I gave an instruction to the … department in charge of the affairs with (the) enemy to decisively carry out the next action,” Kim said.

Her statement, which did not specifically detail what “the next action” might be, came days after South Korea took legal action against defectors who have been sending material such as rice and anti-North leaflets, usually by balloon or in seaborne bottles, over the heavily fortified border.

“The South and the North should try to honour all inter-Korean agreements reached,” the Unification Ministry said in a statement on Sunday.

“The government is taking the current situation seriously.”

To mark its displeasure, North Korea has severed inter-Korean hotlines and is threatening to close a liaison office between the two governments.

-with AAP