Israeli Defence Minister Avigdor Lieberman said on Tuesday that President Bashar al-Assad has been "victorious" in Syria's civil war and was now being courted by former enemies.

"Assad has emerged victorious in the battle," Avigdor Lieberman told Israeli news website Walla!.

"Suddenly, everyone wants to get closer to Assad," he said.

"I see that there is now a long line of countries applauding and wooing Assad, including Western (and) moderate Sunni Muslim (states)."

Assad's fortunes have changed dramatically since Russia launched a military intervention to shore up his forces in 2015 and he now appears well on top after a series of key victories.

Israel has previously called on Assad to step down, but officials have sought to avoid getting too heavily involved in the conflict.

Israel has accused Assad-backer Iran of transferring sophisticated weapons to Lebanon's Hezbollah and has sporadically struck weapons convoys to the Shiite movement inside the war-ravaged country, as well as Syrian government forces.

Israel and Syria have technically been in a state of war for decades and the Jewish state has become alarmed at the growing Iranian influence in Damascus.

Lieberman said they were hoping for increased American involvement to counterbalance the Iranian threat.

"We hope that the United States will be more active on the Syrian front and in the Middle East in general. We are on the northern front against the Russians, Iranians, Turks and Hezbollah," he said.

Israeli Prime Minister Benjamin Netanyahu admitted last year Israel had carried out dozens of attacks on weapons convoys destined for Hezbollah.