Hundreds of Palestinians are starting to repair tunnels in Gaza that are used for smuggling in goods from Egypt.
Israel, which ended its 22-day offensive last Sunday, has warned of renewed military strikes on the strip if the tunnels are reopened.
Residents along the border say food, fuel and other goods are moving through the several dozen tunnels that are still operational.
Meanwhile, attempts continued in Egypt to find a lasting truce.
The talks, with an Israeli envoy Amos Gilad, were expected to focus on stemming arms smuggling across the border.
'Hamas trying to rearm'
Destroying the network of tunnels was one of Israel's main aims when its offensive began in late December.
The Israelis say they are used to smuggle weapons in to militants from Hamas, but the Palestinians argue that Israel's tight control of their borders means the tunnels are the only way they can get enough supplies to survive.
Journalists on the border report that the smugglers are actively working but say that it is impossible to assess if Hamas and other Palestinian militant groups have resumed their smuggling operations.
But Israel says it believes Hamas is trying to rearm.
Mark Regev, Israeli Government spokesman, said: "What is important is that there is today an international coalition; America, Europe, Arab governments will act in unison to prevent Iranian rockets from reaching the Gaza Strip, to prevent the smuggling of weapons into Gaza.
"Hamas will not be allowed to rearm."
One tunnel owner told Reuters: "I will not bring [in] drugs or weapons, I plan to use it to bring in what people need most - food and fuel, and that is very profitable."
He told the news agency, he and three partners had paid $40,000 (£29,177) to build their supply line.
"We have to make a living. We are still young and we have no other job except in the tunnels."
Reconstruction struggle
Before their offensive in Gaza was over, Israeli officials said they had destroyed 60% to 70% of the hundreds of tunnels.
Israel bombed the tunnels heavily during its offensive. The AFP news agency quoted Israeli foreign minister Tzipi Livni saying: "Things must be clear - Israel reserves the right to react militarily against the tunnels once and for all."
Meanwhile, during a visit to the Gaza Strip, the United Nations humanitarian envoy, John Holmes, said the situation there was "extremely shocking".
Mr Holmes is on the first of a five-day trip to the region. He said that without freedom of access to Gaza, for goods and people, the reconstruction effort would struggle.
Low-level violence on both sides has marred the cease-fire. Palestinian medical workers in Gaza City say at least two people were wounded in shelling by an Israeli gunboat.
Restrictions lifted
In Cairo, the issue of border crossings was one of the most contentious, as an Israeli envoy, Amos Gilad, held talks with Egyptian mediators. Hamas officials are expected in Egypt in the coming days.
Israel also says it is lifting the restrictions it has imposed on international journalists entering the Gaza Strip.
The Israeli defence ministry says the normal passage of journalists from Israel to Gaza, at the Erez crossing, would be allowed from Friday. Israel has been restricting access to Gaza for many weeks, and further tightened access after launching its military operations.
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