We compare orbits in a thin axisymmetric disc potential in MOND to those in a thin disc plus near-spherical dark matter halo predicted by a \Lambda CDM cosmology .
Remarkably , the amount of orbital precession in MOND is nearly identical to that which occurs in a mildly oblate CDM Galactic halo ( potential flattening q=0.9 ) , consistent with recent constraints from the Sagittarius stream .
Since very flattened mass distributions in MOND produce rounder potentials than in standard Newtonian mechanics , we show that it will be very difficult to use the tidal debris from streams to distinguish between a MOND galaxy and a standard CDM galaxy with a mildly oblate halo .

If a galaxy can be found with either a prolate halo , or one which is more oblate than q \sim 0.9 this would rule out MOND as a viable theory .
Improved data from the leading arm of the Sagittarius dwarf - which samples the Galactic potential at large radii - could rule out MOND if the orbital pole precession can be determined to an accuracy of the order of \pm 1 ^ { o } .