The tenant refuses viewing
The tenant can initially not deny the landlord to hold viewings if the tenancy is terminated, or the time specified contract is expiring soon.
As landlord you can however not require that the tenant holds the viewings for you. The tenant is only obligated to make the residence available for viewing.
The Tenancy Act section 10-1 gives the right to hold viewingsYou can only hold viewings to a reasonable extent. This means that you cannot require that the residence is available at any given time during the notice period. What is deemed a reasonable extent must be considered specifically based on the residence in question and how much time remains of the tenancy.
Viewings under sub-letting
If the tenant is sub-letting the residence, it is the tenant's responsibility to hold the viewings.
Sub-letting – Can the tenant sub-let the residence to others?