South Korea's President Yoon Suk-yeol said the country will spare no effort to help North Korea, as the isolated nation battles a Covid-19 outbreak, and reiterated he will remain open for humanitarian aid.

"If North Korea responds (to our support), we will spare no medicines including Covid-19 vaccines, medical equipment and health personnel," said Yoon in a speech at the plenary session of the National Assembly today.

Separately in the speech, Yoon also said he will discuss with US President Joe Biden ways to strengthen cooperation on the global supply chain through the Indo-Pacific Economic Framework. Biden is scheduled to visit the country this week.

This came after North Korean leader Kim Jong Un said on Saturday the spread of Covid-19 had thrust his country into "great turmoil" and called for an all-out battle to overcome the outbreak, as 21 daily deaths were reported among people with fever.

North Korea this week acknowledged for the first time a Covid-19 outbreak, imposing a nationwide lockdown. But there was no sign of a rigorous testing or treatment campaign in the isolated country's rudimentary healthcare system.

"The spread of the malignant epidemic is a great turmoil to fall on our country since the founding," Kim told an emergency meeting of the ruling Workers' Party, according to state news agency KCNA.

"But if we don't lose focus in implementing epidemic policy and maintain strong organisation power and control based on single-minded unity of the party and the people and strengthen our epidemic battle, we can more than overcome the crisis."

The numbers probably represent a fraction of total cases, given North Korea's limited testing capabilities, and could lead to thousands of deaths in one of only two countries without a vaccination campaign, experts have said.

The outbreak could also deepen a dire food crisis, with the lockdown hampering anti-drought efforts and mobilisation of labour.

The Workers' Party meeting heard reports of about 280,810 people being treated and 27 deaths since a fever of unidentified origins was reported starting in late April, KCNA said.

State media did not say whether the new deaths were due to Covid-19. One death had been confirmed from the Omicron variant, KCNA said on Friday.

Since late April, 524,440 people have shown signs of fever including 174,440 new cases on Friday, KCNA said. About 243,630 have been treated but KCNA has not said how many people have been tested or confirmed the total number of Covid-19 cases.

North Korea has been testing about 1,400 people a week, according to Harvard Medical School's Kee Park, who has worked on healthcare projects in the country, not nearly enough to survey the hundreds of thousands of people with symptoms.

- Reuters