Signal's owner, San Francisco-based Open Whisper Systems, said that it had investigated complaints over connectivity issues from Egyptians and "have confirmed that Egypt is censoring access to Signal."
In a statement posted to Twitter , the group that it would begin "deploying censorship circumvention" in the coming weeks.
It was not immediately possible to reach Egyptian officials for comment on the alleged ban today.
The Associated Press was unable to immediately verify whether the block was in place or how it worked.
More From This Section
Communications disruptions aren't unusual in Egypt, a country which drew global attention after a nationwide internet blackout in 2011.
Authorities cut web access in an attempt to disrupt plans for massive demonstrations against the then-President Hosni Mubarak, a tactic that backfired after millions still took to the street.
Signal itself has won an increasingly high profile as the encryption protocols behind it are incorporated into more mainstream messaging services such as Facebook's WhatsApp.