HOUSTON (Reuters) -Lawyers representing holders of a defaulted Venezuelan bond and some bidders that participated in a U.S. auction of shares in the Venezuelan parent of U.S. refiner Citgo Petroleum are getting ready to object to the auction's recommended outcome, three sources close to the preparations said.

The challenge to the $7.4 billion offer by a group led by a unit of miner Gold Reserve could again derail the sale of Venezuela's priced foreign asset, which has been put on the auction block to compensate creditors who lost billions to the South American country's expropriations and defaults.

Proceeds from the court-organized auction of PDV Holding are expected to compensate up to 15 creditors fighting since 2017 to recover nearly $19 billion in U.S. courts.

A court officer overseeing the latest bidding round, the second organized to auction the parent of Houston-based Citgo Petroleum after a failed round last year, last week recommended an offer by Gold Reserve's subsidiary Dalinar Energy Corporation to Delaware Judge Leonard Stark.

Dalinar's offer, however, did not include an agreement to pay holders of a key defaulted Venezuelan bond collateralized with Citgo equity, which is expected to be the main reason for objections, the sources said.

The sources added that lack of clarity about the evaluation criteria also is worrying some bidders and creditors.

A pact with the bondholders is seen by some participants as essential to clear the way for a transfer of the shares to the winning consortium, while others say the holders first need to win in a New York court, where they are fighting to have their claim enforced.

Stark will receive objections to the recommended bid through July 9. Any competing bidder can also disclose its offer's terms to challenge the winner. A final hearing on the sales process is scheduled for August 18.

A $7.3 billion offer by an affiliate of hedge fund Elliott Investment Management was rejected last year by most creditors, creating the need for a new bidding round this year.