  Context. The putative tori surrounding the accretion disks of active galactic
nuclei (AGNs) play a fundamental role in the unification scheme of AGNs.
Infrared long-baseline interferometry allows us to study the inner dust
distribution in AGNs with unprecedented spatial resolution over a wide infrared
wavelength range.
  Aims. Near- and mid-infrared interferometry is used to investigate the
milli-arcsecond-scale dust distribution in the type 1.5 Seyfert nucleus of NGC
3783.
  Methods. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band
and compared our observations with models.
  Results. From the K-band observations, we derive a ring-fit torus radius of
0.74 +/- 0.23 mas or 0.16 +/- 0.05 pc. We compare this size with infrared
interferometric observations of other AGNs and UV/optical-infrared
reverberation measurements. For the interpretation of our observations, we
simultaneously model our near- and mid-infrared visibilities and the SED with a
temperature/density-gradient model including an additional inner hot 1400 K
ring component.
