"Let people who long for battles in Gaza not worry. They will take place," local radio quoted Barak as saying.
Hamas, the Islamic group running the 1.5-million-inhabitant enclave, saw an element of election campaigning in Barak's words and warned Israel against such "short-sighted steps."
"We warn Barak and his government of losers against short-sighted steps for which a high price is to be paid. Security cannot be reached through crime and terror," a statement distributed on behalf of Hamas spokesman Fawzi Barhoum said.
For the past 1 1/2 months a ceasefire between Israel and Hamas in Gaza has mostly been observed.
The Gaza Strip has been controlled by Hamas since June last year, leaving Palestinian President Mahmoud Abbas in charge of only the West Bank. Fatah and Hamas have been bitterly divided since then.