Hellenic Petroleum, Greece's biggest oil refiner, plans to refinance outstanding debt in the second half of the year as its cash flow has improved and it expects better conditions in the Greek debt market, the firm said on May 11.

"We are preparing ourselves for a possible refinancing, assuming that markets conditions will be conducive to such an initiative, meaning being able to attract lower coupons and improved terms on a market transaction," CFO Andreas Shiamishis told an analysts conference.

Hellenic had net debt of 2.5 billion euros (US$2.86 billion) in the first quarter of 2016.

It was generating 400-600 million euros of operating cash flow and expected at least 200-300 million euros of free cash to deleverage and pay some dividends moving on into 2016, 2017 and 2018, Shiamishis said.

Hellenic posted on May 11 a 17% drop in first quarter core profit, hurt by lower refining margins.

Core profit or clean EBITDA, stripping out inventory-holding losses, came in at 169 million euros (US$193.03 million), down from 205 million in the same period last year.

The figure was better than analysts' average forecast of 164.5 million euros in a Reuters poll.

Including inventory-holding losses, EBITDA drpped 17 percent to 129 million euros.

Hellenic expects that a stalled sale of a 66% stake in Greece's natural gas grid operator DESFA to Azerbaijan's SOCAR will be cleared by September and hopes to collect about 200 million euros in proceeds by early next year.

($1 = 0.8755 euros)