[en] Kondo semimetal CeRu₄Sn₆ is attracting renewed attention due to the theoretically predicted nontrivial topology in its electronic band structure. We report hydrostatic and chemical pressure effects on the transport properties of single- and poly-crystalline samples. The electrical resistivity ρ(T) is gradually enhanced by applying pressure over a wide temperature range from room temperature down to 25 mK. Two thermal activation gaps estimated from high- and low-temperature windows are found to increase with pressure. A flat ρ(T) observed at the lowest temperatures below 300 mK appears to be robust against both pressure and field. This feature as well as the increase of the energy gaps calls for more intensive investigations with respect to electron correlations and band topology. (paper)