South Korea's health minister has apologised for Covid-19 vaccine shortages, saying US drugmaker Moderna Inc will deliver less than half its planned shipment this month due to production issues.

Suffering a fourth wave of infections, South Korea has posted record numbers of new cases in recent weeks, while its inoculation campaign has been dogged by vaccine shortages and shipment delays.

Health Minister Kwon Deok-cheol has said Moderna had informed South Korea that it would only be able to deliver less than half the 8.5 million doses it had been due to ship in August.

"I once again apologise for causing concerns among the people because of Moderna's vaccine supply problems," Kwon told a briefing.

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