The enhanced preionisation efficiency of a mutually coupled parallel spark preioniser has been exploited to achieve switchless operation of a transversely excited atmosphere (TEA) CO2 laser in the conventional transverse gas flow configuration. This made the laser more compatible to repetitive operation and the satisfactory performance of a switchless TEA CO2 laser of ∼8 cc active volume is reported here up to a maximum repetition rate of 100 Hz at a gas replenishment factor of ∼2.