A landlord or their agent can enter your home for an inspection without your consent, provided they have given seven days notice in writing. If notice is posted, the landlord/agent must allow an extra four working days for delivery.
They are allowed to do this a maximum of four times per year. Have a look at the TenantsNSW fact sheet HERE.
If you are uncomfortable with this arrangement and can't be there yourself, you might want to get a friend or neighbour to attend on your behalf.