UPDATE 2-Poland wants EU to pledge at least 1 bln euros to stabilise Belarus

(Adds more Polish PM comments, details)

VILNIUS, Sept 17 (Reuters) - Poland wants the European Union to offer Belarus financial assistance of at least 1 billion euros ($1.18 billion) as part of a "Marshal plan" to rebuild the country, Prime Minster Mateusz Morawiecki said on Thursday.

Mass protests have gripped Belarus since President Alexander Lukashenko claimed a victory in Aug. 9 election that opposition says was rigged.

Lukashenko, who denies the allegations, cracked down on protesters and on Monday secured a lifeline loan of $1.5 billion from Russia in a gesture of support.

Morawiecki, whose call for a "Marshall Plan" alluded to Europe's reconstruction after World War Two, said the financial assistance forms part of the support package for Belarus which he will propose at the next EU summit on Sept. 24-25.

"The fund should indeed be significant. ... It should be at least 1 billion euros," Morawiecki said in Vilnius after meeting Lithuanian Prime Minister Saulius Skvernelis.

International Monetary Fund (IMF) could also contribute the fund, meant to prop up Belarus currency, stabilize its economy and allow the country to borrow on its own, Morawiecki said.

The plan also includes an opening of EU markets to Belarus businesses and easier visas to its citizens, to make Belarus economy less reliant on cheap energy from Russia, he said.

But the opening should exclude "businessmen who stand against freedom and support the current Belarus government."

Lithuania and Poland's partners in the Visegrad Four grouping - Hungary, the Czech Republic and Slovakia - support the plan, Morawiecki said.

Polish daily Rzeczpospolita said on Thursday the proposed aid would be conditional on Lukashenko allowing a free presidential election.

($1 = 0.8476 euros) (Reporting by Andrius Sytas and Marcin Goclowski Editing by Jason Neely and Tomasz Janowski)