even if you are not a Polish citizen or resident
Not all do --I can think of at least one bank that will not if they have you on record as not tax resident. Unless you change your tax status at their bank, they don't issue a certificate, or so they told me
My question is this: for interest earned on deposits (savings) in Poland during the previous tax year (for example 1 Jan 2013-31 Dec 2013)
does this interest have to be declared on any PIT (or any other) tax return to the Poland tax office along with any other income earned in Poland during that tax year? My accountant said no because tax is deducted by the bank at 19% anyway. But that doesn't sound like the correct procedure because what if the tax office needs to adjust a person's tax band up or down -- surely they'd need to know what interest you received and what tax you already paid. (In the UK, you must declare both gross (untaxed) and nett (taxed) interest to the UK tax office on your return if you submit one.)