The hospital has reviewed security measures

The incident took place at the city's Royal Infirmary on Thursday night.

The female member of staff was not seriously injured but was said to be badly shaken.

Tayside Police confirmed on Saturday that a 34-year-old man had been arrested in connection with the alleged attack.

"A report will be submitted to the procurator fiscal at Perth," said a spokesperson for the force.

The man is expected to appear in court on Monday.

Unions have stepped up calls for the Scottish Executive to take action to protect frontline NHS staff following the alleged attack.

We remain fully committed to a policy of zero tolerance towards violence within all our hospitals Gerry Marr Tayside University Hospitals Trust

NHS Tayside has decided to step up security at the hospital.

A number of police officers will patrol wards, departments and grounds, while additional porters are being brought in to provide escort duties for staff and patients.

It is understood that the measures, which followed a security review, will be in place over the weekend and be assessed on Monday.

The board is also offering personal alarms to staff working on the hospital's 16 wards.

Gerry Marr, chief executive of Tayside University Hospitals Trust, said: "We try to ensure all our premises are as secure as possible while still being accessible to the public.