Low-ionisation structures (LISs) are commonly found in planetary nebulae (PNe), but they are still poorly understood. The recent discovery of unforeseen molecular hydrogen gas (H_2_) has impacted what we think we know about these microstructures and PNe. To obtain an overall understanding of LISs, we carried out an [FeII] 1.644um imagery survey in PNe with LISs, with the aim to detect the [FeII] 1.644um emission line, a common tracer of shocks. We present the first detection of [FeII] 1.644um line directly associated with the LISs in four out of five PNe. The theoretical H I 12-4 recombination line was also computed either from the Brgamma or the Hbeta line and subtracted from the observed narrow-band line fluxes. The [FeII] 1.644um flux ranges from 1 to 40x10^-15^erg/cm^2^/s and the intensity from 2 to 90x10^-5^erg/s/cm^2^/sr. The R(Fe)=[FeII]1.644mu/Brgamma line ratio was also computed and found to range between 0.5 and 7. In particular, the [FeII] 1.644um line was detected in NGC 6543 (R(Fe)<0.15), along with the outer pairs of LISs in NGC 7009 (R(Fe)<0.25) and the jet-like LISs in IC 4634 (R(Fe)~1) and in several LISs in NGC 6571 (2