Hospital emergency departments see an estimated 750,000 people with head injuries each year.
Most cases are mild and do not lead to hospital admission.
The updated guidance states: 'GPs should receive training, as necessary, to ensure that they are capable of assessing the presence or absence of risk factors.'
Risk factors include any loss of consciousness as a result of injury, persistent headache and any suspicion of a skull fracture.
GPs should also check for focal neurological deficits since the head injury, such as problems understanding speech, reading or writing, says NICE.
Loss of balance, decreased sensation and abnormal reflexes, are also risk factors. Any patient identified with risk factors should be sent to A&E via the ambulance service.
Professor Peter Littlejohns, clinical and public health director at NICE, said: 'For injuries that are moderate or severe, it's vital that health professionals can quickly and effectively diagnose and manage these cases.'