  A good fraction of GRBs detected by Swift are at a large redshift (up to
z=6.3, so far). Their study allows us to investigate, among other things, the
cosmic star formation in the early Universe (possibly up to the re-ionization
era) and the chemical enrichment of the high-redshift gas. Here we present and
discuss a method of selection which identifies high-redshift candidates based
only upon promptly-available information provided by Swift. This method relies
upon, Galactic extinction, GRB duration time and absence of an optical
counterpart in the UVOT telescope onboard Swift. This tool may provide an
extremely effective way to locate high-redshift astrophysical objects and to
follow them in the optical/NIR band in near real time.
