I would say that it is not safe if they can't successfully perch on it. I wouldn't use it if I were you. Parakeets aren't like us, perches are their beds and are their chairs. Very important to them.
Cloud and Sonny and Frosty(RIP)
Snow glistens upon the open field, I see your shape, I hear your chirp, and happiness fills my soul, knowing how happy you must be, to be away from me....RIP Frosty! I'll love you forever and for always!