European Union antitrust regulators said last month that PKN's bid for Lotos may reduce competition in Poland and neighbouring countries and push up prices.

BP has the biggest petrol station network in Poland after PKN Orlen.

"If the EC (European Commission) decides that the market structure needs opening up a bit after the merger, then of course we and other companies would be happy to enter into any discussion about assets that potentially could be for sale," BP head of Europe Peter Mather told Reuters on Tuesday.

"That could be anything across the whole value chain," he said in an interview on the sidelines of an economic conference in southern Poland.

State-run PKN, which has a market capitalisation of 39.01 billion zlotys (£8.09 billion) said last year that it planned to buy at least a 53% stake in Lotos, which is valued at 16.14 billion zlotys, from the government.

It has formally requested approval from EU regulators for the deal to go ahead. Sources familiar with the situation in Brussels and Warsaw have said that due to competition concerns PKN will likely face long and difficult talks with the European Commission.

BP has already raised its concerns that the merger might harm competition in Poland.

"The concentration issue is now in the hands of the European Commision, we hope that they will take into account our opinion," Mather said.

(Reporting by Marcin Goclowski; Editing by Susan Fenton)

By Marcin Goclowski