Royal Dutch Shell is selling its upstream assets in New Zealand to Austria's OMV AG for $578 million, the companies said on March 15.

"Today's announcement is another step towards reshaping and simplifying our company," Shell's Integrated Gas & New Energies Director Maarten Wetselaar said.

The agreement includes the sale of Mui, Pohokura and Tank Farms. After deal closure, Shell Taranaki and Shell New Zealand employees will become a part of OMV New Zealand, Shell said.

"This acquisition is an important step to develop Australasia into a core region in line with our new strategy," OMV CEO Rainer Seele said.

Shell has sold or agreed to sell over $25 billion of assets as part of a three-year programme to dispose of $30 billion by the end of 2018, following the acquisition of BG Group in 2016.

Shell sold its stake in Kapuni gas field, New Zealand's second-largest, for an undisclosed price in 2017.