Mr Barak also reportedly said Israel would not remove checkpoints from the West Bank for at least several years.
He was quoted by the newspaper Yedioth Ahronoth, which said the remarks had been made in private conversations.
Palestinian Authority President Mahmoud Abbas hosted Israeli PM Ehud Olmert for talks earlier this week.
The talks in the West Bank town of Jericho were highest-level talks on Palestinian territory for some years and involved discussions on the broad principles for establishing a Palestinian state.
According to Yedioth Ahronoth, Mr Barak said Israel would not withdraw its military checkpoints on the West Bank until it has developed defences against rocket attacks from Palestinian territory.
Mr Barak said this would take from three to five years.
Mr Barak's office said there had been "no change in Barak's stance regarding the importance of the political process alongside our obligation to protect Israel's security".
"Israelis have healthy intuition," Mr Barak was quoted as saying by the newspaper. "They can't be fed more fantasies about an upcoming agreement with the Palestinians."
A US-sponsored Middle East peace conference is set to take place in November.
The Israelis have been trying to bolster Mr Abbas and his Fatah faction since the militant Hamas faction took over the Gaza Strip in June, splitting the Palestinian territories between the two groups.
Mr Barak is the leader of the left-leaning Labour Party in Mr Olmert's ruling coalition.
He was prime minister in the late 1990s and came close to reaching a peace agreement that would have given up much of the West Bank to the Palestinians.
The talks - which included a Camp David summit with the late Palestinian leader Yasser Arafat and US President Bill Clinton - broke down after the outbreak of the Palestinian intifada (uprising) in late 2000.
Soon after that, Mr Barak was voted out of office.
Last Mod: 13 Ağustos 2007, 15:53