  In this paper we present a fully relativistic approach to modelling both the
continuum emission and the reflected fluorescent iron line from a primary X-ray
source near a Kerr black hole. The X-ray source is located above an accretion
disc orbiting around the black hole. The source is assumed to be a static point
source located on an arbitrary position above the disc, on or off the axis of
rotation. We carry out Monte Carlo simulations in order to estimate the iron
line spectrum as well as its equivalent width. Because of the gravitational
lensing effect, an enhancement of the iron line is expected when the primary
source is located close to the central black hole. We find that for a source
located on the axis of rotation the enhancement is relatively modest. An
observer at inclination 30 degrees would measure an equivalent width of ~300eV
in the extreme case of a maximally rotating black hole and a source located at
height 1.5 gravitational radius from the centre. This corresponds to an
equivalent width enhancement factor of about 2 compared to the classical value
where no lensing effect comes into play. However, when allowing the source to
be located off the axis of rotation, much stronger enhancement can be obtained.
In the extreme case of a maximally rotating black hole and a source located
just above the approaching side of the disc, an observer at inclination 30d
egrees could measure an equivalent width as high as ~1.5 keV (i.e. ~10 times
the classical value). We also find that observers located at high inclination
angles observe a stronger line than observers at low inclination angles.
