  Within the $\Lambda$CDM cosmology, dark matter haloes are expected to deviate
from spherical symmetry. Constraining the halo shapes at large galactocentric
distances is challenging due to the low density of luminous tracers. The
well-studied early-type galaxy NGC 5128 (Centaurus A - CenA), has a large
number of radial velocities for globular clusters (GCs) and planetary nebulae
(PNe) of its extended stellar halo. In this work, we aim to determine the
deviation from spherical symmetry of the dark matter halo of CenA at 5 $R_{\rm
e}$ using its GCs as kinematic tracers. We used the largest photometric
catalogue of GC candidates to accurately characterise the spatial distribution
of the relaxed population and investigated the presence of non-relaxed
structures in the kinematic catalogue of GCs using the relaxed point-symmetric
velocity field as determined by the host's PNe population. We used anisotropic
Jeans modelling under axisymmetric assumptions together with the Gaussian
likelihood and GCs as discrete tracers. The gravitational potential is
generated by flattened stellar and dark matter distributions. We leveraged
different orbital properties of the blue and red GCs to model them separately.
We find that discrete kinematics of the GCs are consistent with being drawn
from an underlying relaxed velocity field determined from PNe. The best-fit
parameters of the gravitational potential recovered from the blue and red GCs
separately agree well and the joint results are: $M_{200} =
1.86^{1.61}_{-0.69}\times 10^{12}$ M$_\odot$, $M_\star/L_{\rm B} =
2.98^{+0.96}_{-0.78}$ and the flattening $q_{\rm DM} = 1.45^{+0.78}_{-0.53}$.
Both GC populations show mild rotation, with red having a slightly stronger
rotational signature and radially biased orbits, and blue GCs preferring
negative velocity anisotropy. An oblate or a spherical dark matter halo of CenA
is strongly disfavoured by our modelling.
