Staff and families at Christchurch's Ronald McDonald House are devastated by a burglary over the weekend.

Thieves broke in through the Cashel Street entrance on Friday night, making off with a safe containing cash and private details.

The 26-bedroom house was full on Friday, with families and their sick children sleeping metres away from the robbery.

CEO Matthew Mark says everyone's extremely upset, and the families had a huge fright.

"Obviously the families experienced first hand how important is for us to be here for them to provide this facility and for someone to come in and take advantage of that is not only disappointing but upsetting to the families."