The CFMEU administration has purged more than a dozen officials across the country in just three weeks as it ramps up action to clean out the construction union after the High Court dismissed a challenge to its existence.

The approximately 15 organisers who quit, were sacked or accepted voluntary redundancies in the past month represent almost half the 32 who have departed since the administration was imposed in August, union sources said. The 32 include 11 senior officials ousted at the start of the administration.