The short answer is no unless there are no other living persons to whom the estate may be distributed. There is a structure for the distribution of an estate which is described in another answer.
For NSW I would suggest you review the NSW State Trustee and Guardian web site. There is a useful discussion of wills.
It is best to have a will so that this issue does not arise. If you are asking the question and can still make a will I suggest you do so!
It is likely that your employer has a policy on working a second job. Look first at HR policies. Your employment agreement and/or award where applicable may also deal with this issue.
A general issue is whether or not the second job may conflict in some way with the interests of your primary employer. The other issue is whether working a second job will impact on your ability to perform the duties of your primary job. Eg coming to work exhausted because of your secondary job.