HAMBURG (Reuters) - German Finance Minister Peer Steinbrueck said newspaper reports about government plans to sell Germany's biggest retail bank, Deutsche Postbank (DPBGn.DE: Quote, Profile, Research), to Commerzbank (CBKG.DE: Quote, Profile, Research) or Deutsche Bank (DBKGn.DE: Quote, Profile, Research) were speculative.

"That is all speculation," Steinbrueck said on the margins of a meeting of Social Democrat party leaders on Monday, when asked about the newspaper reports.

Germany's Handelsblatt newspaper reported on Monday that the government had plans to sell Postbank this year, preferably to Germany's second-biggest bank, Commerzbank.

Handelsblatt cited government sources for its story.

The "Rheinische Post" newspaper reported that Postbank was to be sold to the country's biggest bank, Deutsche Bank, while the Westdeutsche Allgemeine Zeitung added that Royal Bank of Scotland (RBS.L: Quote, Profile, Research), HSBC (HSBA.L: Quote, Profile, Research) and a Dutch bank had also signaled interest.

A spokeswoman for Deutsche Post (DPWGn.DE: Quote, Profile, Research), Postbank's owner, declined to comment on the reports.

Departing Deutsche Post Chief Executive Klaus Zumwinkel said late last year that the company would consider what to do with Postbank this year and that many banks were interested in it.

In recent weeks, the chief executives of both Deutsche Bank and Commerzbank have said they were interested in Postbank, which is worth around 10 billion euros ($14.6 billion).

Postbank's head, Wolfgang Klein, said on Friday that the bank would play a role in the consolidation of the German banking sector, though he stressed that it was not currently in concrete talks with potential partners.

(Reporting by Markus Krah and James Regan, writing by Jonathan Gould, editing by Will Waterman)