What is that? Christchurch memorial marred after mystery brown substance flung at Gerry Brownlee

Labour leader Andrew Little has come to the defence of political rival Gerry Brownlee after the Earthquake Recovery Minister had a "brown substance" tipped over him today.

Gerry Brownlee had a foul-smelling substance tipped on him after a memorial service in Christchurch today. Source: 1 NEWS

The incident happened following a memorial service to commemorate the fifth anniversary of the Canterbury Earthquake.

A man walked up to Mr Brownlee and tipped an ice cream container containing "pretty mucky stuff" over his head.

Mr Little said he was disgusted by the incident.

"Totally unacceptable, this is a community occasion where we commemorate and reflect on a great tragedy," he told ONE News.

"For some scumbag to come and do that to anybody, doesn't matter if it's one of my political opponents, is totally unacceptable."

He said people may have legitimate gripes with how the rebuild is progressing, but that was not the way to highlight a complaint.

"It's a despicable thing to do in any context, at any time, and is not a way to make your point."

A 41-year-old man has been arrested and charged with assault over the incident.

He will appear in the Christchurch District Court tomorrow. 

Mr Brownlee told NZME that he didn't want to speculate about what was in the container.

"Didn't smell too good," he said.

The incident capped a tough day for Mr Brownlee, who had a live interview with Radio New Zealand interrupted by a heckler.