Poland's financial watchdog chief will head to Ireland as early as next week to discuss the sale of Bank Zachodni WBK , the Polish unit of AIB, sources told Reuters today.

The move is seen by analysts as adding to efforts by Polish authorities anxious to strengthen the banking sector by reducing foreign control currently, which is currently around 70%.

Warsaw is concerned that foreign domination could expose its banking system and wider economy to grave risk if parent banks withdraw funding in a future financial crisis.

But a concerted effort favouring a domestic buyer could put Poland at odds with European Union regulators.

Earlier this week, Polish Treasury Minister Alexander Grad threw his weight behind PKO BP's likely bid for AIB's 70% stake in BZ WBK, worth some $3 billion.

PKO is expected to face off against several large European banks, including UniCredit, Santander, BNP Paribas and Russia's Sberbank. An industry source said preliminary bids are due on Monday and binding offers would be required in September.