  We search for very small-diameter galactic planetary nebulae (PNe)
representing the earliest phases of PN evolution. A recently published IPHAS
catalogue of Ha-emitting stars provides a useful base for this study as all
sources present in this catalogue must be of small angular diameter.
  The PN candidates are selected based on their location in two colour-colour
diagrams: IPHAS (r' - Ha) vs. (r' - i'), and 2MASS (J - H) vs. (H - Ks).
Spectroscopic follow-up has been carried out on a sample of candidates in order
to confirm their nature.
  We present a total of 83 PN candidates. We were able to obtain spectra or
find the classification from the literature for 35 candidates. Five of these
objects are likely to be new PNe, including one large bipolar PN discovered
serendipitously near an emission-line star. PN distances deduced from
extinction-distance relations based on IPHAS field-star photometry are
presented for the first time. These yield distance estimates for our objects in
the range from 2 kpc to 6 kpc. From the data to hand, we conclude that four of
the discovered objects are very probably young PNe.
