SEOUL - South Korean biotech firm GL Rapha expects to win regulatory approval from Russia to export Sputnik Light coronavirus vaccines this month, its chairman said, paving the way for the first overseas production of the shot to ease a supply shortage.

The Russian Direct Investment Fund (RDIF), which markets Sputnik V and single-dose version Sputnik Light abroad, plans to produce around 700 million doses overseas this year.

But production got off to a slow start and growing domestic demand constrained supply from Russia, disrupting both shots' global rollout plan and allowing rival vaccine makers to fill the gap in several markets.

"Everything is pretty much ready and we continue to produce the vaccine as we wait for Russia to validate our production process," GL Chairman Whang Jae-gan said in an interview.

He said the RDIF, the Russian sovereign wealth fund, had informed the firm that approval was expected later this month, and it is preparing a joint ceremony to mark the first overseas vaccine production and shipment.

RDIF declined to comment.

GL, which oversees the entire production of the vaccine from drug substance to packaging in its facility in Chuncheon, east of Seoul, has at least 10 million doses of Sputnik Light already in storage ready for shipment pending approval.

It comes more than a year after the two sides first started cooperation talks, which accelerated following technology transfer by its Russian developer Gamaleya Research Institute in October, underscoring the complicated process facing global efforts to rapidly boost vaccine supply.

"We needed to act decisively and decided to put all our resources into it," Whang said, adding he was encouraged by confidential clinical data presented to it even before a deal was agreed.

He said the company suspended all other drug production, and boosted efforts to scale up and generate synergies.

In April, just six months after the technology transfer, GL sent out a validation batch for Sputnik V, and around the same time the RDIF also asked the company to produce Sputnik Light concurrently. GL is now awaiting a Good Manufacturing Practice (GMP) nod from Russia for its production facility.

The company has scaled up production far exceeding its initial target of 650 million doses per year through its consortia that include botox-maker Jetema Corp, CKD BiO Corp, Hankook Korus Pharm, and Boryung Biopharma, a vaccine manufacturing arm of Boryung Pharm, Whang said.

He declined to elaborate on exact capacity.

While the RDIF will decide which nations get the vaccine first, it's likely to be sent to various countries that have reported delays, Whang said.

Production is also set to accelerate elsewhere, with Serum Institute of India planning to manufacture trial batches from this month.

Six Indian companies have already signed deals to produce around 1 billion doses of Sputnik V annually.

(Reporting by Sangmi Cha; Additional reporting by Anton Zverev in Moscow; Editing by Miyoung Kim & Shri Navaratnam) ((sangmi.cha@thomsonreuters.com;))