We report results of the benchmarking of core particle transport simulations by the codes widely used in the interpretative transport analyses and predictive modelling of tokamak plasmas. Our analysis includes formulation of transport equations, difference between electron and ion particle solvers, comparison of simulations of particle sinks and sources including modelling of the pellet and the edge gas fuelling on the ITER baseline scenario. At the first phase of benchmarking we address the particle transport effects related to the stationary phase of operation. Firstly, simulations are carried out with identical particle sources, sinks, transport coefficients, and boundary conditions for one time slice prescribed in the flattop H-mode phase. The transformation of the ion particle transport equations is introduced so that their results can be directly compared to the electron solvers. Secondly, the pellet fuelling models are benchmarked in various conditions to evaluate the dependency of the pellet deposition profile on the pellet volume, the injection side, the pedestal parameters, and the separatrix parameters. Thirdly, edge gas fuelling is benchmarked to assess sensitivities of the source profile predictions with respect to uncertainties in background plasma conditions and detailed model assumptions. At the second phase of benchmarking, we address the particle transport effects in the time-evolving plasma including the current ramp-up to the ramp-down phase. The ion and the electron solvers are benchmarked together with prescribed evolutions of the plasma configuration, particle transport coefficients, sources, and boundary conditions. The transport solvers present good agreement within 6% in the whole benchmarking. The origin of differences are investigated in terms of the equilibrium, number and distribution of grid, and the role of terms describing the evolution of the plasma volume. We found that the number of grid and the selection of the radial coordinate in the solvers can show prominent differences between the solvers through the grid distribution particularly at the edge. The simulations reveal that electron and ion particle transport solvers predict noticeably different density peaking for the same diffusion and pinch velocity in presence of the peaked profile of helium, expected in fusion reactors. The fuelling benchmarking shows that in the case of ITER, in contrast to present machines, gas puffing is not efficient for core fuelling in the H-mode operation and density control should be done by the high field side (HFS) pellet injection. Core fuelling in ITER-like plasmas is shallow, the source is located mainly within the outer 20% of plasma radius.