  The epoch of reionisation progressed through the emission of ionising photons
from galaxies to their local intergalactic medium. In this work, we
characterise the dwarf star-forming galaxies as candidates for the source of
ionising photons that drove EoR. We investigate the ionising properties and
star formation histories of star-forming dwarf galaxies at the last stages of
EoR at $4.8<\rm{z}<7$ using observations from the CAnadian NIRISS Unbiased
Cluster Survey (CANUCS). The magnification due to gravitational lensing allows
us to probe large dynamic ranges in stellar mass ($2\times
10^{6}\leq\rm{M}_*/\rm{M}_\odot\leq5\times 10^{9}$) and UV magnitudes
($-22.68\leq$M$_{UV}\leq=-15.95$).We find a median UV slope \buv of $-2.
56\pm0.23$ and the production efficiency of ionising photons $\log$ \xiion
$=25.39\pm0.6$ for the full sample ($4.8<\rm{z}<7$) with a median stellar mass
of $6.3\pm0.5\times10^{7} \rm{M}_\odot$. We find both \buv and \xiion are
marginally correlated with the stellar mass of the galaxy, indicating a
possible greater contribution of dwarf galaxies to the reionisation of the
Universe. We find that on average, galaxies in our sample are experiencing a
recent rise/burst of star formation which translates to a higher scatter in
\xiion and a large scatter in H$\alpha$ equivalent widths. Finally, we
investigate the trends of H$\alpha$ and [OIII]+H$\beta$ EWs with UV magnitude
and find M$_{UV}$ is correlated between H$\alpha$ but not with [OIII]+H$\beta$
EWs indicating low metallicities and recent burst in the UV faint galaxies.
