  We studied seven nearby narrow-line Seyfert 1 (NLS1) galaxies in $J$- and
$Ks$-bands with redshifts varying from 0.019 to 0.092. This is the first
multi-source study targeting the hosts of southern NLS1 galaxies. Our data was
obtained with the FourStar instrument of the 6.5~m Magellan Baade telescope at
the Las Campanas Observatory (Chile). The aim of our study is to determine the
host galaxy morphologies of these sources by using GALFIT. We were able to
model six out of the seven sources reliably. Our conclusion is that all of the
reliably modelled sources are disk-like galaxies, either spirals or
lenticulars. None of these sources present elliptical morphology. Our findings
are in agreement with the hypothesis that disk-like galaxies are the main host
of jetted NLS1 galaxies. Taking advantage of observations in two bands, we also
produced a $J - Ks$ colour map of each source. Five of the six colour maps show
significant dust extinction near the core of the galaxy -- a feature often seen
in gamma-ray-detected jetted NLS1 galaxies, and interpreted to be a consequence
of a past minor merger.
