Tajani was addressing a bilateral conference in Rome about the country's eventual reconstruction.
He said Rome was pushing for Moscow to be made to pay damages at the international level.
He also stressed that Italy is intent on helping to lead the efforts required to rebuild the battered nation.
"The reconstruction is a fundamental part of the effort that we Italians, we Europeans, want to make for Ukraine in a concrete way," Tajani said.
"It is an important step because Ukraine will be part of the EU and part of the single market.
"So it is right to start work.
"The reconstruction starts now and we want to be on the front line, laying down the foundations."
Speaking at the same conference, Ukrainian Foreign Minister Dmytro Kuleba thanked Italy for its commitment to support Kyiv in the long term.
"The interest shown by Italian businesses is the best news that we could have received as we landed in Rome," Kuleba told the conference, involving more than 600 Italian firms.
"I thank the (Italian) institutions and companies for being at Ukraine's side and for the long-term commitment. Contacts between our governments are more dynamic than ever".
Ukrainian Prime Minister Denys Shmyhal also expressed gratitude to Italy during a press conference with Italian Prime Minister Giorgia Meloni.
"Our countries have reached a new level of partnership," Shmyhal said.
"The reconstruction starts now.
"We are united in the defence (of Ukraine) and we are united in the reconstruction".
Shmyhal also thanked Meloni for her total "360-degree" support.
"Italy has been key in supporting Ukraine's EU adhesion and we will remember it," he said.
Ukraine needs $14 billion for its "most urgent priorities" in 2023, European Investment Bank (EIB) Vice President Gelsomina Vigliotti said at the conference.
"It is necessary to concentrate on investments that cannot wait until the end of the war," Vigliotti said.
"We must address these needs now, supporting the economy to avoid further losses and further damage...
"We are ready to support the Italian partners (in projects in Ukraine) in sectors such as infrastructure, energy resilience, agriculture, construction and transport."
ANSA