St John said emergency services attended the incident in Fiordland National Park, near Lake Manapouri, about 9am today.
A police spokeswoman said a rescue helicopter was able to winch the woman out about 12.15pm.
‘‘Police understand the woman was hit by a falling branch and felt near Iris Burn Hut.’’
It appeared she had broken several bones, the spokeswoman said.
St John said the woman was in a serious condition and airlifted to Dunedin Hospital.