Vietnam has temporarily suspended the use of its first home-grown African swine fever vaccine after dozens of pigs inoculated with the shots died this month, state media reported on Wednesday.

The pigs were among around 600 pigs at several farms in the central province of Phu Yen having been injected with the NAVET-ASFVAC vaccine developed by Navetco, a company owned by the agriculture ministry, reported Nhan Dan newspaper.

"We have set up a working group to travel to the province to investigate the deaths of the pigs," said an agriculture ministry official, who declined to be named as he's not authorised to speak to media.

Navetco didn't immediately respond to a Reuters request for comment.

African swine fever is harmless to humans but often fatal to pigs. It originated in Africa before spreading to Europe and Asia and has killed hundreds of millions of pigs.

It was first detected in Vietnam in 2019 and forced the country to cull around 20% of its hog herd the following year.

The outbreak has so far this year spread to 753 areas in 47 provinces in Vietnam, leading to the culling of 36,500 pigs, according to the agriculture ministry.

Vietnam in June announced that it had successfully developed a vaccine to administer to pigs to fight African swine fever, with the aim of becoming the first country to commercially produce and export it.

The agriculture ministry had earmarked 600,000 doses of the vaccine for domestic use from July this year.