>>>can this be done without me being present?
Yes but anyone doing so would be wisest to get someone else to witness the search so that
(a) it's clear that nothing was removed ; and
(b) it's also clear that nothing was 'planted'.
Most employers would have policies to cover situations where a lockers contents are examined without the employee being present. (In some cases such searches might be urgent. For example if it was thought that you might have accidentally left the key to something important in your locker, your colleagues would need to be able to see if it was there).