The electrical properties of wurtzite-type ZnO low-dimensional structures were analysed using a scanning tunnelling microscopy (STM) in situ holder for transmission electron microscopes (TEM). Compared to similar studies in the literature employing nanowires or nanobelts, our work illustrates that rather complex structures can be reliably analysed with this technique. Through controlled contact manipulations it was possible to alter the systems I-V characteristics and, in separate experiments, to follow their electrical response to cycles of induced stress. Analysis of the I-V curves showed higher than expected resistances which, according to the detailed TEM characterisation, could be correlated with the considerable density of defects present. These defects accumulate in specific areas of the complex structural arrays of ZnO and represent high resistance points responsible for structural failure, when the systems are subjected to extreme current flows.