Poland’s ruling party has approved a controversial draft law that will eventually ban shops from opening on Sundays.

According to the draft legislation, retail businesses will be forced to close two Sundays a month in 2018 and remain closed all Sundays (with few exceptions) by 2020.

Backed by the labour unions and the Catholic Church, critics warn the ban could hurt economic growth and hit corporate profits.

Since Poland’s economy is based largely on domestic consumption, many companies depend on weekend shopping for a large part of their sales, according to a report published by Bloomberg.

For instance, the country’s largest clothing retailer, LLP SA, counts on Sunday shoppers for 18% of revenue. Also, household consumption was the main driver of economic growth in the third quarter.

In an interview with Bloomberg, Michal Dybula, a Warsaw-based economic strategist at Bank BGZ BNP Paribas, said: “Any restriction of economic activity, such as retail trade, results in weaker economic growth. It may impact the earnings of affected companies, but consumers might also react by stockpiling goods”.

To become law, Poland’s upper house of parliament now needs to approve the bill. And then, President Andrzej Duda will sign it into law.

In a separate report, the Catholic Herald online noted that the Polish bishops’ conference welcomed the bill but said it did not go far enough, and that everyone should be free from work on Sundays.