Oamaru Hospital says it had no option but to close its Emergency Department at night this weekend because of the nationwide doctor shortage.

The department is closed between 5pm and 8am tonight and tomorrow, but will be open during the day.

The hospital says local GPs and residential care facilities have been advised and some ward patients potentially moved to Dunedin Hospital.

Oamaru Hospital says it has been working closely with Te Whatu Ora over the past few weeks to address the doctor shortage but the health agency was unable to provide coverage to prevent the closure.

In July, RNZ reported that Christchurch Hospital's emergency department was under resourced and under pressure, after seeing a record 412 people in a 24 hour period.

Earlier in July, Christchurch's only 24-hour surgery, Pegasus Health, was forced to close its doors for almost three hours due to high demand.