The report said the problem could be worse than reported

Workers in Welsh hospitals report an average of 22 daily incidents of verbal or physical abuse costing the NHS �6m every year.

And the auditor general for Wales said under-reporting could be hiding the true extent of the problem.

A nursing union said the situation should not be allowed to continue.

You don't know when that is going to escalate from verbal abuse to actual physical abuse Naomi Gibson, staff nurse

One nurse has spoken of delayed shock and distress after being punched repeatedly.

Naomi Gibson, a staff nurse at the accident and emergency department in Prince Charles Hospital, Merthyr Tydfil, said staff are often confronted with verbal assault on a daily basis.

She said she later needed to take time off work after being attacked as she tended to a patient.

She said: "I was working an afternoon shift, an ambulance crew brought a patient in, I was treating her and going to do her blood pressure, she started hitting out.

"I advised the nurse with me to go out and phone police and security. I walked out behind her, [the] patient jumped up off the trolley and grabbed hold of my uniform, punched me twice in the head.

"I managed to push her down on the trolley and she again punched me another twice on the head.

"I had redness to the side of my head and my face where I had been punched, [I was] mostly shaken up, frightened."

'Distress'

Ms Gibson said the shock of what happened to her did not sink in until later.

"When you first get attacked it's like you are running on adrenalin - you are shaking but you carry on," she said.

"It wasn't until a week later really it hit home and I had to go on the sick because I was really physically shaking and distressed."

She added: "Mostly on a daily occurrence we have verbal assaults in A&E which are quite threatening and again that brings back all the frightening experience I had on that day when I was physically assaulted - you don't know when that is going to escalate from verbal abuse to actual physical abuse.

"You feel like you are fighting a losing battle and it seems the more we try the worse we are treated, " she added.

The Welsh assembly audit committee report, Protecting NHS staff from Violence and Aggression, said trusts are complying with legal obligations and guidelines on protecting staff.

But it added that there are still gaps in information collected about the nature and causes of incidents.

The Welsh Assembly Government has shown some leadership in tackling the problem but more, much more, needs to be done Tina Donnelly, Royal College of Nursing

Improvements on data collection and risk assessments of some patients - who are delayed in being transferred - are called for in the report.

Last September the Auditor General for Wales, Jeremy Colman, said the problem could be much worse because of under-reporting.

The Royal College of Nursing director Tina Donnelly said steps had been taken but more needs to be done.

Ms Donnelly said: "It is a state of affairs that cannot be allowed to continue.

"To date the Welsh Assembly Government has shown some leadership in tackling the problem but more, much more, needs to be done."

In 2003-04, NHS trusts in Wales spent �6.3m dealing with violent incidents as well as on prevention through training and security.