Solomon Islands has closed its borders to incoming travellers indefinitely in a bid to keep the delta variant of Covid-19 out of the country.

Neighbouring countries Fiji, Papua New Guinea and Australia continue to grapple with the deadly variant with Fiji the worst affected with over 22,000 active cases, and over 230 deaths since April.

Solomon Islands Health Minister Culwick Togamana announced the new travel restrictions on Monday.

"We are not allowing any incoming passenger services whether by air or by sea from the countries reporting community transmission of the delta variant.

As of now all the incoming flights will only be cargo flights and no passengers will be coming until further notice," he said.

Dr Togamana said the government will use the time the border is closed to upgrade and strengthen MIQ facilities and processes.

All public servants and private sector front-line workers in Solomon Islands have been ordered by government to get fully vaccinated by the 30th of November or have their employment terminated.

Togamana announced the mandatory vaccination alongside the new travel restrictions for the country.

The edict covers all public servants and employees of state-owned-enterprises as well as private sector employees working in front-line roles.

Togamana said the strict conditions were a proactive response to the rapid spread of the delta variant of Covid-19 in Fiji, Papua New Guinea and Australia.

"Any person covered under the above categories who chooses not to get their first doses of vaccination by 31st of August will not be allowed to access their place of employment.

And any person not fully vaccinated by the 30th of November 2021 will be taken as having chosen to self-terminate their employment," he said.