Power workers’ industrial action has delayed the NSW government’s critical western Sydney interchange for the city’s second airport by months and is sending subcontractors close to the wall.

The Electrical Trade Union’s work bans at Sydney poles and wire company Endeavour Energy, including refusing to switch off powerlines, has set back key work on the $1.7 billion project to link the M7 with the new toll-free M12 motorway by up to four months. The integration is needed to feed into Western Sydney Airport when it opens in 2026.