He said that pinpoint aviation strikes and local raids were not effective enough to stop the rocket attacks on Israeli towns bordering Gaza.
"We are getting closer to carrying out a widespread operation in Gaza which for many reasons has not taken place in the past weeks," Barak said on Israel's Army Radio.
"It must be clear that an operation of this type is not simple, not in terms of the forces and the amount of time which we will have to stay there or in terms of the operational challenges which the troops will have to meet," he said.
Israel's Air Force twice attacked Palestinian rocket launch sites in northern Gaza on Wednesday, the Israeli Army press service said.
The Israeli air strikes, which, according to Palestinian radio, wounded one Palestinian teenager, came in response to five rockets launched at southern Israel on Tuesday by Palestinian militants.
Three of the rockets exploded near population centers, but there were no reports of casualties. Responsibility for the attacks was claimed by al-Quds Brigades, a military wing of the Islamic Jihad movement.
Israeli troops are continuing their operations in the West Bank, and have so far arrested seven Palestinians suspected of involvement in terrorist activity.
Eyewitnesses said that Israeli aviation also hit a car in Gaza Wednesday, killing at least three Palestinian militants. According to unconfirmed reports, the militants belonged to the Islamist group Hamas, which has controlled the Gaza Strip since June.
September has seen Palestinian militants sharply intensify rocket attacks, including a Qassam rocket attack on the Zikim Israeli military training base on September 11 that caused injuries to around 70 recruits.
Although Hamas did not participate in the attack, it congratulated the Palestinian people on a "Victory from God."
"Of course, we welcome the attack. We consider it a worthy answer to the crimes of the occupants," said a Hamas spokesman. A spokesman for Islamic Jihad said: "The jihad continues - we have one language, the language of guns and rockets."
On 12 September 2005 the Israeli cabinet officially announced the end of military rule in the Gaza Strip, more than 38 years after they had captured the area in the 1967 Arab-Israeli War. The move came after a popular uprising against Israeli occupying forces.
Last week, Israel declared the Gaza Strip, with a population of 1.5 million, an "enemy entity," and said it would reduce fuel and power supplies.