"It is shameful and I hope the Syrian people know that this government doesn't represent the Lebanese will," Lebanon's former Prime Minister Saad Hariri said in a message posted on Twitter.
"This is not the Lebanese will that voted, it is the Hezbollah government headed by (Najib) Mikati," added Hariri, who leads the pro-Western opposition camp in Lebanon.
Hariri has been living abroad since Hezbollah brought down his government in January.
The Arab League suspended Syria on Saturday until President Bashar al-Assad implements an Arab deal to end violence against protesters, and called for sanctions and transition talks with the opposition.
Yemen, Syria and Lebanon were the only countries to vote against the measures adopted by the 22-member regional bloc, while Iraq, which like Lebanon neighbours Syria, abstained.
"Finally the Arabs took their responsibilities towards the plight of the Syrian people seeking freedom, democracy and dignity," Hariri tweeted.
The turmoil in Syria has driven a wedge between Hezbollah, which supports Assad's regime, and the opposition in Lebanon which resents Damascus for its 30-year political and military control over its smaller neighbour.
Asked by a Twitter user whether he thought the fall of Assad's regime would have negative repercussions for the Middle East, Hariri said: "No I think it will be the best thing for the region."
The Assad regime was widely blamed for the 2005 assassination of Saad's father Rafiq Hariri, who was also Lebanon's prime minister, but Damascus has always denied any involvement.