Slovenia on Wednesday temporarily suspended vaccinations with Johnson & Johnson after a 20-year-old woman died of a brain haemorrhage and blood clots just days after getting a jab.

"The health ministry has called on the Public Health Institute to temporarily suspend vaccinations with he Janssen vaccine until all details related to this case are cleared up," Health Minister Janez Poklukar told a news conference in Ljubljana, using another name for the jab.

Experts advising the government recommended the suspension after learning that "there could be an undesired link between the death and the vaccination," said Bojana Beovic, who heads the expert group.

Media reported the woman had been hospitalised on Monday in severe condition, only days after receiving a Johnson & Johnson jab.

One death has already been confirmed as linked to the vaccine in Slovenia, where more than 120,000 people have been jabbed. 

Some 47% of the Alpine nation's two million people have been fully vaccinated, one of the lowest levels in the European Union.

In an attempt to boost numbers, the government announced earlier this month that all public employees would need to be vaccinated or recovered from COVID-19 to continue working from October 1.

Demand for Johnson & Johnson has increased over the last weeks because it is the only vaccine that does not require two jabs.

The European Medicines Agency said in June that EU states must use all the vaccine options available to fight the coronavirus pandemic, and it was too early to tell if a particular type was best.

The comments came as several countries limited the use of so-called viral vector jabs like AstraZeneca and Johnson & Johnson due to a link with rare blood clots, and opted instead for Messenger RNA vaccines like Pfizer and Moderna.

The regulator has currently approved those four vaccines for use in the 27-nation EU.