A new law banning Sunday trading in Poland has come into effect, with supermarkets and other retail outlets closed. 

The legislation, sought by the Solidarity trade union and supported by the Catholic Church, will limit shopping to the first and last Sundays of the month. 

Next year trade will only be allowed on the last Sunday of the month before a wider ban halts shopping on most Sundays from 2020. 

The Solidarity trade union said it introduced the change to ensure retail staff get free time at the weekends. 

The liberal opposition and other critics argue it will limit job opportunities for students and affect cross-border shopping from the Baltic states, Belarus, Ukraine and Slovakia. 

The law applies to foreign-owned hypermarket chains as well as other non-Polish outlets.

It will still allow shopping online and at smaller locally-owned shops including bakeries and petrol stations.

The ban was first proposed by Solidarity in 2016.

The right-wing Law and Justice (PiS) government, which is close to the Catholic Church, got behind the ban and passed the legislation in November. 

Sunday shopping became a popular family pastime in Poland with the advent of the free market after the collapse of communism in 1989. 

Hungary backtracked on a similar ban after it proved widely unpopular. 

Switzerland and Norway limit Sunday shopping, while Austria has a blanket ban. 

Up to now, stores in Poland have remained closed for 12 days a year for major national or religious holidays.