It's not the first time Labour has been left red-faced after copyright breaches.
In 2015, then-MP Clare Curran was forced to apologise for lifting paragraphs from business magazine The Economist for an issues paper on the "Future of Work".
Prime Minister Jacinda Ardern. Photo / Mark Mitchell
"A large number of documents were used during the research for this paper, from many sources over a period of weeks and months," she said.
"These paragraphs should have been cited in the final text and I apologise for the oversight. The document has been updated on our website."
National Party leader Simon Bridges told Newshub the latest round of plagiarism wasn't good enough from the Labour Party.
"In fact, it's much worse than that. They've literally cut and pasted from their Google searches into their Labour Party material and brochures."
Labour MP for Mt Roskill and Chief Whip Michael Wood said plagiarism of any form was unacceptable.
The party would correct the document and "get it back out there, because this is actually a really well-loved resource that many older people enjoy receiving".