We have undertaken a deep (σ ~ 1.1 mJy) 1.1-mm survey of the z =
0.54 cluster MS0451.6-0305 using the AzTEC camera on the James Clerk
Maxwell Telescope. We detect 36 sources with signal-to-noise ratio (S/N)
>= 3.5 in the central 0.10 deg2 and present the AzTEC map,
catalogue and number counts. We identify counterparts to 18 sources (50
per cent) using radio, mid-infrared, Spitzer InfraRed Array Camera
(IRAC) and Submillimetre Array data. Optical, near- and mid-infrared
spectral energy distributions are compiled for the 14 of these galaxies
with detectable counterparts, which are expected to contain all likely
cluster members. We then use photometric redshifts and colour selection
to separate background galaxies from potential cluster members and test
the reliability of this technique using archival observations of
submillimetre galaxies. We find two potential MS0451-03 members, which,
if they are both cluster galaxies, have a total star formation rate
(SFR) of ~100Msolaryr-1 - a significant fraction
of the combined SFR of all the other galaxies in MS0451-03. We also
examine the stacked rest-frame mid-infrared, millimetre and radio
emission of cluster members below our AzTEC detection limit, and find
that the SFRs of mid-IR-selected galaxies in the cluster and
redshift-matched field populations are comparable. In contrast, the
average SFR of the morphologically classified late-type cluster
population is nearly three times less than the corresponding
redshift-matched field galaxies. This suggests that these galaxies may
be in the process of being transformed on the red sequence by the
cluster environment. Our survey demonstrates that although the
environment of MS0451-03 appears to suppress star formation in late-type
galaxies, it can support active, dust-obscured mid-IR galaxies and
potentially millimetre-detected LIRGs.