Brazil's Ultrapar is set to submit an offer for Royal Dutch Shell's European liquefied petroleum gas (LPG) arm alongside a string of private equity bidders, the Financial Times reported.

The Brazilian fuel and natural gas company is expected to submit a bid for the assets on Tuesday, the paper said on its website on Sunday.

Other possible bidders include private equity firms PAI, Advent International, Axa Private Equity, CVC Capital Partners and First Reserve, the FT said. Mexico's Grupo Zeta Gas could also submit an offer, according to the paper.

Anglo-Dutch Shell has hired Credit Suisse to sell its European LPG arm for as much as $1 billion, as the group seeks to shed downstream assets to focus on more lucrative oil and gas production.

However, the auction could be stalled due to opposition from French unions over the sale of the LPG arm, which includes the Paris-based Butagaz business, the paper said, citing a person familiar with the matter.

Shell declined to comment. The other parties could not immediately be reached for comment.

(Reporting by Caroline Copley; Editing by Diane Craft)