* Vetro says to deposit guarantee in a few days
* Vetro's Taci confident of a deal, sees lot more work
* Albania to be flexible if Vetro pays guarantee bond
TIRANA, Dec 11 (Reuters) - Vetro Energy, an Albanian-U.S. firm that made the top bid for Albanian state-owned oil company Albpetrol, said on Tuesday it would soon make a deposit as a guarantee so that the 850 million euro ($1.1 billion) sale can go ahead.
On Monday, a week after a second deadline to sign a contract expired, Albania held off signing a sale contract for Albpetrol again, saying Vetro had failed to deposit 20 percent of its offer in cash or an equivalent to cash, which is required to back the sale.
Deputy Energy Minister Sokol Dervishaj said the government would give Vetro another chance if it made the deposit.
Albanian oilman Rezart Taci, who has emerged as Vetro's majority shareholder, said in a statement that Vetro had asked the government for "a number of additional documents".
In return, the government demanded a guarantee, "which Vetro Energy is pleased to provide and will be in place within the next few days," he said.
He added that "a guarantee of this nature is customarily submitted only after a formal contract is signed" and that there was still "significant work ahead" to thrash out a deal.
Vetro had offered to buy 100 percent of Albpetrol for 850 million euros, which means its deposit to guarantee the contract would amount to 170 million euros.
"These are complex discussions and there is a great deal of detail involved. The delay is not entirely surprising in such circumstances, and I am very confident that we will finalise negotiations and reach a successful conclusion," Taci said.
The government welcomed Taci's pledge with caution.
"If Vetro deposits an unconditional contract guarantee bond in a few days as it officially committed today, we'll have the adequate flexibility to consider the fulfilment of their expressed commitment and continue with the negotiations," Dervishaj, also the sale board chairman, told Reuters.
Four years ago, Taci's Anika Enterprises teamed with Refinery Associates of Texas and Mercuria Energy Group to buy Albanian refiner ARMO for 125 million euros. ARMO is Albpetrol's biggest debtor at 5,374,445,691 lek ($49.7 million), according to the state audit commission.