Papua New Guinea authorities have warned of falling pumice, ash, unpredictable swells and turbulent currents.

The Titan Ridge Volcano is erupting in the Bismarck Sea, sending ash and smoke into the sky and prompting authorities to warn of possible tsunamis in the area.

Papua New Guinea authorities have warned of falling pumice, ash, unpredictable swells and turbulent currents.

The volcano's activity has been described as rare and unusual, and coastal communities living around PNG's Bismarck Sea have been advised to be on heightened alert.