A court has ordered Switzerland to stop sending groups of vulnerable asylum seekers back to Italy, warning that reception conditions had recently worsened, according to a ruling published Friday.

Switzerland's Federal Administrative Court found last month that conditions in Italian migrant reception centres had "deteriorated across the board" since the introduction of a new immigration law in late 2018.

This poses in particular a problem for vulnerable and traumatised people, the court found, ruling that Bern can no longer send groups of vulnerable migrants to Italy but must now seek assurances of suitable conditions in each individual case.

Switzerland has been sending asylum seekers back to neighbouring Italy under Europe's embattled Dublin Regulation, which entrusts the processing of asylum applications to the first country of entry.

Swiss media said that last year 610 people were sent back to Italy under the Dublin agreement.

Italy has long complained that under this system it shoulders an unfair burden.

Between June 2018 and August 2019, Italy was governed by a coalition comprised of the anti-establishment Five Star Movement and the far-right League.

League leader Matteo Salvini, who served as interior minister at the time, enacted a range of measures to curb migration, including levying fines on rescue boats run by charities that plucked migrants from the Mediterranean Sea.

The Swiss ruling published Friday, which cannot be appealed, pointed in particular to Salvini's legislative degree 113/2018.

This law, which took effect in November 2018, had had "a wide-ranging impact on how asylum seekers in Italy are accommodated", the court said in a statement. The legislation among other things blocked access to so-called "second-line" centres, which included measures for caring for particularly vulnerable asylum seekers, including families with children and people with severe health problems, it pointed out. The law "presents asylum seekers with additional obstacles that make it harder for them to begin proceedings immediately and access support services," the court said, adding that "standards also vary greatly from region to region".

Despite these issues, the court concluded that access to asylum proceedings were still guaranteed in Italy, and that the system there had "no systemic weaknesses".

This means, it said, that "transfers under the Dublin procedure are still permissible as a basic principle."