Règle correspondante
Practice Relating to Rule 55. Access for Humanitarian Relief to Civilians in Need
Section C. Access for humanitarian relief via third States
The Military Manual (2005) of the Netherlands states:
A neutral State may allow the passage of … relief goods belonging to parties to the conflict (HC [1907 Hague Convention respecting the Rights and Duties of Neutral Powers and Persons in Case of War on Land] Article 14). It should ensure that no battle units or military equipment are included. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0936.