diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -1990,10 +1990,6 @@
             self.network_address = IPv6Address(address)
             self._prefixlen = self._max_prefixlen
             self.netmask = IPv6Address(self._ALL_ONES)
-            if strict:
-                if (IPv6Address(int(self.network_address) &
-                                int(self.netmask)) != self.network_address):
-                    raise ValueError('%s has host bits set' % str(self))
             self.network_address = IPv6Address(int(self.network_address) &
                                                int(self.netmask))
             return
@@ -2004,13 +2000,9 @@
             self.network_address = IPv6Address((tmp[0] << 64) | tmp[1])
             self._prefixlen = self._max_prefixlen
             self.netmask = IPv6Address(self._ALL_ONES)
-            if strict:
-                if (IPv6Address(int(self.network_address) &
-                                int(self.netmask)) != self.network_address):
-                    raise ValueError('%s has host bits set' % str(self))
-                self.network_address = IPv6Address(int(self.network_address) &
-                                                   int(self.netmask))
-                return
+            self.network_address = IPv6Address(int(self.network_address) &
+                                                int(self.netmask))
+            return
 
         # Assume input argument to be string or any object representation
         # which converts into a formatted IP prefix string.