Henryk Kowalczyk also told Reuters that if the calculations of the financial watchdog were to be confirmed, it would be a reason to spread the cost of the bill over time.

Poland's financial watchdog said on Tuesday a proposed bill to convert foreign currency mortgages into zlotys could cost local lenders up to eight times their 2015 profits, potentially pushing one of Europe's healthier banking sectors into crisis.

(Reporting by Pawel Sobczak; Writing by Marcin Goettig)