Netanyahu made the comments in Rome, broadcast live in Israel, after Israel and Turkey agreed on a highly anticipated deal to end years of acrimony and restore ties.
Relations soured after a deadly 2010 Israeli raid on an aid flotilla seeking to run the blockade on Gaza.
"The second thing the agreement gives is continuation of the maritime security blockade off the Gaza Strip coast," Netanyahu said.
"This is a supreme security interest for us. I was not prepared to compromise on it."
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Israel says the blockade is necessary to keep out material that could be used for military purposes in the strip run by Islamist movement Hamas.
At the same time, UN and aid officials have warned of deteriorating conditions in the Palestinian enclave, which has one of the world's highest unemployment rates.
Part of the deal reached with Turkey reportedly involved a compromise in which Israel will allow the completion of a much-needed hospital in Gaza, as well as the construction of a new power station and a desalination plant for drinking water.