Results. The new APEX observations allowed us to identify three molecular components, each one associated with different regions of the nebula, namely: at -39 km s(-1) (component A), -25 km s(-1) (component B), and -17 km s(-1) (component C). Component A is shown to be the most dense and clumpy. Six molecular condensations (MC1 to MC6) were identified in this component, with MC3 (the densest and more massive one) being the molecular counterpart of IRAS 12326-6245. For this source, we estimated an H-2 column density up to 8 x 10(23) cm(-2). An LTE analysis of the high density tracer lines HCO+ (3-2) and HCN (3-2) on this source, assuming 50 and 150 K, respectively, indicates column densities of N(HCO+) = (5.2 +/- 0.1) x 10(13) cm(-2) and N(HCN) = (1.9 +/- 0.5) x 10(14) cm(-2). To explain the morphology and velocity of components A, B, and C, we propose a simple model consisting of a partially complete semisphere-like structure expanding at similar to 12 km s(-1). The introduction of this model has led to a discussion about the distance to both S169 and IRAS 12326-6245, which was estimated to be similar to 2 kpc. Several candidate YSOs were identified, projected mostly onto the molecular condensations MC3, MC4, and MC5, which indicates that the star-formation process is very active at the borders of the nebula. A comparison between observable and modeled parameters was not enough to discern whether the collect-and-collapse mechanism is acting at the edge of S169. However, other processes such as radiative-driven implosion or even a combination of both mechanisms, namely, collect-and-collapse and radiative-driven implosion, could be acting simultaneously in the region.