Last month’s snow and ice has caused delays to the building of the new Ysbyty Ystrad Fawr hospital near Ystrad Mynach.
The £172million project is about ten days behind schedule.
The cold weather and snow delayed the completion of some external building work which then held up the start of some internal fitting.
Health bosses have said the delay is being reviewed and monitored and that building work will be rescheduled to make up for lost time.
Ysbyty Ystrad Fawr, which will replace the historic Caerphilly Miners’ Hospital, is due to open in autumn 2011 and will be the biggest new hospital built in Wales for 30 years with 255 beds.
It will be one of the first hospitals in the country to have single en-suite rooms for every patient.