"Syria believes it need do nothing more than let itself be courted by the world, while saying one thing and doing the opposite," Peres, whose post is largely ceremonial, said amid Israeli media reports of rising tensions.
He made the comments just hours before flying to Paris, where he is expected to discuss the issue with French President Nicolas Sarkozy.
Israel's Deputy Defence Minister Matan Vilnai declined to go into details of the alleged Scud shipments but said that "Hezbollah's firing capacity has significantly improved."
Israel accuses both Syria and Iran of supplying arms to the Shiite Muslim Hezbollah, whose deadly attack on an army patrol just inside Israel triggered a devastating in the summer of 2006.
In February, Prime Minister Benjamin Netanyahu accused Lebanon of allowing Hezbollah to develop its stockpile of weapons.
Israel estimates Hezbollah's arsenal at some 40,000 rockets, a significant rise from the group's 14,000 rockets in 2006, when the 34-day conflict killed 1,200 Lebanese, mostly civilians, and more than 160 Israelis, mostly soldiers.
It says the stockpile includes rockets with a range of more than 300 kilometres (116 miles), capable of reaching major Israeli population centres.
Vilnai said that Israel would again conduct military exercises this year to prepare for possible rocket attacks by Hezbollah.
Hezbollah is blacklisted by Washington as a terrorist organisation, although it is part of a Lebanese coalition government formed in November by US- and Saudi-backed Prime Minister Saad Hariri.
Israel remains technically at war with Syria and Lebanon.
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