The implosion dynamics of a high-density fibre plasma driven by a spinning Z-pinch is investigated. Spin coupling with the inner fibre plasma is taken into consideration. Numerical results show that the coupling can affect the plasma dynamics and reduce the maximum achievable density and temperature. Thus the large spin needed to prevent the Rayleigh-Taylor instability can adversely affect fusion conditions. For intermediate spin and coupling, high densities and temperatures can be realized for fibres seeded with high-Z impurities.