"Merely stating that Lebanese parties are interfering in Syrian affairs is equivalent to threatening to destabilise Lebanon, irrespective of whether charges of funding and arming the protesters are accurate," said Ghassan el-Ezzi, professor of political science at the state-run Lebanese University.
"This could well be an attempt to transfer the crisis from one country to another," Ezzi told AFP.
Damascus and Beirut have a turbulent history. Syria first sent its troops into Lebanon at the height of the country's 1975-1990 civil war, where they remained for 29 years.
Syria withdrew its forces from Lebanon in April 2005, following the assassination of Saudi-backed ex-premier Rafiq Hariri, father of the current acting prime minister Saad Hariri.
The two countries formally established diplomatic ties for the first time in October 2008, and along with Iran Syria continues to back a Hezbollah-led camp in Lebanon.
Syria has accused Saad Hariri's alliance, which has the support of the United States and Saudi Arabia, of backing Syrian protesters who have taken to the streets since March in increasingly angry rallies demanding an end to 48 years of Baath party rule.
Experts say the charge may be an early sign that Lebanon could suffer the consequences of unrest in Syria.
"Undermining stability in Lebanon is an easy matter: any dispute here will turn into sectarian strife in which Arab states, Iran, Turkey and Western countries, such as France and the United States, get involved," Ezzi said.
State-run Syrian television aired alleged confessions by three members of a "terrorist group" who said they had received funds and arms from Lebanese MP Jamal Jarrah, a member of Hariri's Sunni Future Movement, to rise up against the regime of President Bashar al-Assad.
Damascus's ambassador to Lebanon, Ali Abdelkarim Ali, has called for a local investigation into the case.
Hezbollah's Al-Manar television also reported that Syrian authorities confiscated drugs, money and arms on seven boats that had been heading from northern Lebanon to the Syrian port city of Latakia.
Syria "suspected the boats were tied to the Future Movement," Al-Manar said.
Some analysts say there is no smoke without fire.
"While there is no concrete evidence, I do not think it is a totally far-fetched notion that there is arms and cash smuggling from Lebanon to Syria with the help of Saudi Arabia," said Karim Makdisi, a political science professor at the American University of Beirut.
But, Makdisi said, whatever aid made it across the border could not be significant enough to play a crucial role in the current events in Syria.
"These are exaggerated scenarios, and more likely part of the ongoing dance between Hezbollah and Hariri," he told AFP.
Hundreds of Syrians have also fled on foot across the border into northern Lebanon, after violence broke out in the Syrian town of Tall Kalakh, a majority Sunni area notorious for cross-border smuggling.
Lebanon has also been the scene of rallies both against and in support of Assad, with security forces dispersing two opposing gatherings in Beirut on Tuesday night.
Around 300 supporters of pan-Islamic group Hezb Ut-Tahrir also rallied last week in Lebanon's mainly Sunni northern city of Tripoli after Friday Muslim prayers to show support for protesters in Syria.
As the Syria uprising shows no sign of fading, members of Hariri's alliance fear developments in their northern neighbour could harm an already tense situation in Lebanon.
"Syria should first and foremost stop the bloodshed within its borders, rather than broadcast fabricated lies that only serve to tarnish what is left of its government's image," MP Okab Sakr of Hariri's bloc told AFP.
"And Hezbollah's participation in these lies only serves to further divide Lebanon politically."