Climate change activists have taken their protest to the steps of Simon Bridges' electorate office in Tauranga.
The National Party leader posted to Facebook that his property had been defaced by members of Extinction Rebellion, a global environmental protest group.
A black oil-like substance has been dribbled across the steps with an Extinction Rebellion symbol visible.
"I respect your right to protest Extinction Rebellion but not when it comes to defacing people's property as you've done to my electorate office overnight," Bridges wrote.
Extinction Rebellion said in a post on Facebook the protest was in response to global oil giant OMV's presence in New Zealand waters - and the dirty "oil" was in fact "organic molasses".
Groups from Tauranga, Opotiki and Waihi along with Greenpeace had "joyfully marched" to Bridges' office to call for OMV's oil exploration to end.
Protester Doug Doig, 61, had poured the molasses, risking arrest in the protest.
"It's time for us Boomers to start getting vocal about what dirty oil is doing to this country. This is a climate and ecological emergency- we need people like National Party leader Simon Bridges to tell the truth about the state of things."