Syria arrested 10 dissidents in May who had signed the Damascus-Beirut declaration, a document urging the Baathist government to mend ties with Lebanon that have been damaged since last year's assassination in Beirut of Rafiq al-Hariri, a former Lebanese prime minister.
One of the ten who were arrested was among those sacked.
"The regime is showing no leniency, it wants to decimate dissent. The less international pressure on Syria the more it spreads its totalitarian grip," said Ammar Qurabi, head of the National Organisation for Human Rights.
"These people were fired although they include doctors and engineers in the government for decades," Qurabi said.
A government decree sacking the 17 workers was issued on June 14, another Syrian human rights organisation said.
Syria has been isolated from the West since al-Hariri's killing, subject of a United Nations inquiry.
The Lebanese-Saudi billionaire turned politician was a long-time ally of Damascus who started criticising Syria's dominant role in Lebanese politics and military affairs months before his death.
A UN investigation implicated Lebanese and Syrian security officials in the al-Hariri killing. Damascus denies involvement.
Without suggesting any Syrian role in that event, the Damascus-Beirut declaration condemned political killings and called for the establishment of mutual diplomatic ties, which the two countries have never had since their creation in 1920.
It was signed by hundreds of Lebanese and Syrian activists.
Relations between Syria and Lebanon plummeted after al-Hariri's murder, which forced Bashar al-Assad, the Syrian president, to withdraw forces from Lebanon, invigorated exiled opposition to the Baath Party and put Syrian policies at home and abroad under international scrutiny.