The report said that the dramatic increase is due to a distorting impact of sanctions against Russia.
The developments are based around the ISAB oil refinery on the southern Italian island of Sicily, which Moscow-based Lukoil owns.
Because of sanctions, ISAB is unable to obtain lines of credit for purchases from other crude oil producers, meaning the refinery must rely entirely on supplies from Lukoil, the reports said.
"It's paradoxical because the European Union wanted to penalize Russian energy imports, but here they have actually been incentivized by the sanctions," said Alessandro Tripoli, general-secretary for southern Sicily with the Federation for Energy, Fashion, Chemistry, and related workers, which is part of the CISL trade union.
According to commodity data company Kpler, the dramatic increase means Italy is on the verge of surpassing the Netherlands as the European Union's biggest importer of Russian crude oil.
Earlier this month, the European Union vowed to end imports of Russian crude oil to most member states, including Italy, by the end of this year.