St John Ambulance, already facing more than $13 million in earthquake-related costs, has been forced to lay off four Christchurch employees.
A spokesperson says the administrative staff worked in the organisation's Durham Street building which has a limited access yellow sticker.
The jobs have been moved to Auckland.
Another two of St John's premises - including the main base on St Asaph Street - have red stickers and are unable to be occupied.
In all, 15 of St John's 18 buildings in Canterbury have been damaged.
The repair bill, plus the additional operating costs created by the quakes, comes to more than $13 million.
The organisation's insurance expired on Thursday and although it has managed to secure future insurance, the cover has reduced and the cost has risen.