There are reports of a widespread failure in computer systems affecting the Welsh NHS with GPs saying that they are unable to access patient details.
“There is currently a technical issue affecting two NHS Wales data centres,” a Welsh Government spokesperson said.
“This is under investigation by the NHS Wales Informatics Service and is being dealt with as a priority.”
BMA Wales, which represents doctors, also confirmed there had been a crash on NHS computers.
Email and intranet services are also said to be affected by the problem.
Powys NHS IT department said: “There is currently a major incident affecting a number of nationally hosted systems across NHS Wales.
“The issue appears related to national firewalls and is being currently investigated by NWIS.'”
Dr Alan Woodall, chairman of GP Survival UK who works from a surgery in Montgomeryshire, said: “Myself and colleagues that work in primary care cannot access electronic patient records which is severely inhibiting our ability to provide patient care.
“I’m not sure about hospitals at the moment.
“We are working emergencies only – in middle of influenza/winter crisis this is major impact if continues.”
Another doctor, working from a GP Surgery in the Abertawe Bro Morgannwg health board area that covers Swansea and Bridgend, described it as “chaos”, adding “I can’t do anything. I need this system for everything.”