The Polish financial regulator is expected to approve the sale of AIB subsidiary Bank Zachodni to Santander in "a matter of weeks", according to Polish banking sources and local press reports.

It is understood permission was held up as the Polish Financial Supervision Authority (KNF) sought to assure BZ WBK's listing on the Warsaw stockmarket.

The execution of the sale will net €2.9bn towards AIB's capital in time to meet a 28 February deadline to bring its reserve levels up to 12%. Any further delay in the transaction, which was agreed in principle last August, would have forced the state to increase its financial support of the bank.

"We should expect a decision in the near future. It is a matter of weeks," KNF chairman Stanislaw Kluza told Polish daily Rzeczpospolita. "We are in the process of clarifying issues of investor commitment. KNF wants to keep the bank on the exchange market."

Polish bank PKO, the losing bidder for AIB's 70% stake in BZ WBK, had also raised objections in September that Santander had privileged access to data during the due diligence process.

Last week AIB reported it had raised €1.4bn in a debt exchange. It needs a further €4.7bn to meet the new Central Bank requirements.