Greece's economy is seen expanding by 3.5-4.0% this year due to higher revenues from tourism and strong exports, the country's influential think-tank IOBE said on Wednesday, up from a previous forecast range of 2.5-3.0%.

"Strong revenues from tourism and a sharp increase in Greek exports supports the economic expansion," IOBE head Nikos Vettas told reporters.

Greece hopes that 2022 tourism revenues will reach 90% of their pre-pandemic 2019 level, when it saw receipts of 18 billion euros on the back of 33 million arrivals

IOBE had previously said Greece could see its economy growing by 4-5% annually in the coming three to four years if it implements reforms but Russia's invasion of Ukraine has raised the risk of disruptions to Russian gas flows while also contributing to increased global energy and food prices.

Vettas said IOBE's latest forecast did not take into account possible disruptions in gas imports.

"On the negative side, and aside from the higher energy prices and rising inflation, there are also pressures for a sharp tightening of monetary policy (in the euro zone) that might affect countries like Greece," Vettas said.

Greece, the euro zone's most indebted country, hopes to return to investment grade early next year after its decade-long financial crisis and the COVID pandemic, which hit in 2020. (Reporting by Lefteris Papadimas Ediitng by Gareth Jones)