Classical queueing theory is often not suitable to model modern computer and communication systems, in which the service itself can require random amounts of multiple resources. For instance, this is true for distributed computation and wireless devices connected through different access technologies. To model such systems we propose a resource queueing system with customer duplication, in which the service time and the amount of requested resources in each block are independent random variables. In more detail, we assume that customers arrive according to a general renewal process and, taking advantage of the dynamic screening and the asymptotic analysis methods, we derive a Gaussian approximation for the stationary probability distribution of the occupied resources in the system blocks. Finally, simulation experiments point out the applicability region (in terms of arrival rate) of the proposed approximation. © 2020, Springer Nature Switzerland AG.