We present high and low resolution spectroscopy and narrow-band imagin
g of the unusual bipolar outflow source NGC 6537. As a consequence, we
are able for the first time to construct large scale velocity maps of
this source; note the presence of strongly variable core outflow dens
ities, rising to a peak value n(e) similar to 1.7 10(4) cm(-3); find e
vidence for substantial core ionization stratification; and demonstrat
e the presence of a spatially extended, intermediate velocity wind ext
ending over a range Delta v(1) similar or equal to 700 km s(-1), toget
her with a more tightly constrained component having Delta v similar o
r equal to 4400 km s(-1). This latter wind appears co-spatial with the
slower, higher intensity core emission, and may be responsible for dr
iving denser clumps of material to a typical velocity v(exp) similar t
o 18 km s(-1). Temperatures appear to vary significantly over the core
, from a peak value T-e similar or equal to 1.0 10(4) K close to the n
ucleus, to similar or equal to 0.9 10(4) K for projected radial offset
s of 5 '', whilst extinction is more or less constant, yielding a mean
estimate A(v) similar or equal to 3.4 +/- 0.2 mag. Application of a s
hock outflow model suggests that most of these features are readily ex
plained providing wind mass-loss rates are of order M similar to 6 10
(-8)-6 10(-7) M. yr(-1), and the flow is strongly collimated by an int
erior disk. In particular, we are able to provide excellent simulation
s for both the complex kinematics, and unusual bipolar configuration.