The security forces had seized dozens of kilograms (pounds) of sulphur and 25 grams (just under an ounce) of mercury fulminate "which are used in creating explosive devices," it said in a statement.
Members of the Palestinian Islamist cell had been based in the northern West Bank town of Qalqilya and used a flat in Nablus as an "explosives lab".
Signup to our newsletter and follow us on Facebook and Twitter!
The Shin Bet said the six suspects had confessed during interrogation to having been recruited by Hamas elements in Jordan and sent to Gaza for training.
They then went back to the West Bank to carry out military activity and recruit others.
Shin Bet said it demonstrated the "high motivation" of Hamas's foreign leadership to prepare military units which could eventually carry out attacks.
It did not give any further information on where the alleged attacks inside Israel were to have taken place or when.