"Rescue forces have extracted an additional body from the building that collapsed yesterday in Tel Aviv," an army statement said.
Police spokesman Micky Rosenfeld told AFP that "500 police rescuers, army and firefighters are hard at work trying to find the missing."
"There is no time limit for searches that are concentrated in four areas of the site," he added.
He said an investigation had been opened to determine responsibility for the accident, but had no details yet.
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"There are still people trapped; we are making every effort and are not giving up on anyone. We will reach them all," he said in a statement.
The circumstances of the collapse, which occurred in the Tel Aviv's Ramat Hahayal high-tech neighbourhood, remain unclear.
Israeli media reported the accident occurred when a floor collapsed during the construction of a four-storey underground parking, with a shopping centre eventually planned to be built on top.
The Yedioth Ahronoth newspaper recalled an article from three years ago in which the leader of the Danya Cebus company which built the car park allegedly said they had decided not to use a construction engineer to supervise the work, instead making do with an architect.
Israel has seen a high number of construction accidents in comparison to the developed world.
Haaretz newspaper reported in May that 480 people were killed in construction accidents between 2000 and 2015, citing a survey placing Israel third from the bottom in a list that included the United States and 20 European nations.
Police reported 28 people have been killed on construction sites since the beginning of 2016.