An extra 7000 people will be able to see the inside of Christchurch's CBD red zone with the addition of twilight bus tours starting next Monday.
Canterbury Earthquake Recovery Authority chief executive Roger Sutton hoped the additional trips will ease concerns people may miss out.
Bus tours into the quake-devastated central city, which has been closed since the February 22 aftershock, began last weekend and have proven to be popular with Christchurch residents.
Mr Sutton said the 0800 RING CERA booking line has been "extremely busy" and appreciated how frustrating it is for people trying to get through.
The peak times for calling are between 8am and 9.30am, and lunchtime, so Mr Sutton said people are best to avoid calling then. The booking lines are open on weekdays between 8am and 5pm.