ZURICH (BLOOMBERG) - Switzerland's Federal Intelligence Service is warning of potential terrorist attacks on coronavirus vaccine infrastructure including vaccination centres, transport and manufacturing facilities, newspaper NZZ am Sonntag reported on Sunday (Aug 29).

"Attacks on such targets would both hit large crowds and generate intensive media coverage," the agency's spokesman Isabelle Graber said in a written response to questions from NZZ.

The agency is concerned about attacks from militant groups, the newspaper reported. So far, there are no tangible indications of planned attacks, according to the agency.

Switzerland's vaccine deliveries are coordinated and conducted by the Swiss army. Doses are stored in secret locations.

A spokesman for Lonza Group, a manufacturer of Moderna's vaccine, told the newspaper the company would not comment "on such sensitive topics".

Switzerland has suffered a significant increase in Covid-19 cases and hospitalisations in recent weeks.

The Alpine nation has distributed 9.51 million vaccine doses, enough to cover 55.6 per cent of the population. That is one of the lowest vaccine rates among major economies in Europe.

NZZ also reported that Health Minister Alain Berset said in an interview that mobile vaccination efforts need to be increased.

"The cantons must send out a lot more mobile vaccination teams," Mr Berset said.

The federal councillor also warned that travel restrictions such as mandatory quarantines for returning travellers could be re-introduced.