  In this paper, we present rapid follow-up observations of the short GRB
201006A, consistent with being a compact binary merger, using the LOw Frequency
ARray (LOFAR). We have detected a candidate 5.6$\sigma$, short, coherent radio
flash at 144 MHz at 76.6 mins post-GRB with a 3$\sigma$ duration of 38 seconds.
This radio flash is 27 arcsec offset from the GRB location, which has a
probability of occurring by chance of $\sim$0.05% (3.8$\sigma$) when accounting
for measurement uncertainties. Despite the offset, we show that the probability
of finding an unrelated transient within 40 arcsec of the GRB location is
$<10^{-6}$ and conclude that this is a candidate radio counterpart to GRB
201006A. We performed image plane dedispersion and the radio flash is
tentatively (2.4$\sigma$) shown to be highly dispersed, allowing a distance
estimate, corresponding to a redshift of $0.58\pm0.06$. The corresponding
luminosity of the event at this distance is $6.7^{+6.6}_{-4.4} \times 10^{32}$
erg s$^{-1}$ Hz$^{-1}$. If associated with GRB 201006A, this emission would
indicate prolonged activity from the central engine that is consistent with
being a newborn, supramassive, likely highly magnetised, millisecond spin
neutron star (a magnetar).
