The government has issued a plea after 'a small number' of people with Covid symptoms visited the hospital in recent days and later tested positive for the virus.
Visits were stopped for a fortnight last month after a Covid outbreak in the hospital, caused by a few visitors coming in with symptoms.
They were only reinstated in the adult wards and mental health wards last week.
Visitors are being urged to take a lateral flow test beforehand and to stay away if they have symptoms.
A government spokesperson says visiting guidelines will be reviewed on a daily basis to make sure patients are kept safe and workforce resilience is maintained.
Two named visitors per patient are allowed, with only one able to attend at once.
A record of those visitors is kept by staff.
Hands have to be washed on entrances to clinical areas and masks have to be worn at all times.
21 hospital patients have Covid-19, an increase of nine on Friday 28 January.
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