Green MP co-leader Russel Norman has laid a complaint with police after members of a Chinese delegation were able to push him, hit him with an umbrella and rip a Tibetan flag from his grasp.
Dr Norman was protesting as Chinese Vice-President Xi Jinping arrived at Parliament to be greeted by a few dozen pro-China supporters.
Some of the group, believed to be Chinese security, took exception to Dr Norman waving a Tibetan flag and calling for democracy.
The MP brushed away attempts to have an umbrella placed in front of him, then clashed with security guards as they pulled the flag from his grasp and threw it on the ground.
He yelled they could suppress freedom of speech in China, but not in New Zealand.
Dr Norman said he considered what happened to him an assault.
"I've laid a complaint with the police because New Zealanders need to know they are free to speak without fear of violence or recrimination."
The Prime Minister John Key should speak out, Dr Norman said.
"Because John Key's Government let Chinese security control our Parliament, it stopped being a safe place for democracy.
"I'm asking that John Key make a clear statement that this sort of behaviour is not acceptable in New Zealand."
A meeting between Labour leader Phil Goff and Mr Xi was moved to a hotel rather than at Parliament after the incident.
Immediately after the skirmish Dr Norman told media he was shocked by the incident.
"I think it's pretty outrageous that Chinese security can come to our country and push around an elected member of Parliament simply because we are standing up for democracy and freedom in our own country on our own Parliamentary grounds," Dr Norman told reporters.
He said it seemed most security were Chinese, rather than local.
"Certainly the New Zealand security didn't seem to give a lot of assistance...I mean the Chinese security guards elbowed me out of the way, and then I got an umbrella over the top of me and they took the flags off my hands and trampled on it and there wasn't a lot of support from New Zealand security, that I could see.
"In our country we respect democratic rights and freedom of speech and members of parliament and all citizens of New Zealand should have the right to speak out."
Dr Norman said he was roughed up and his flag trampled before he got it back.
"I will certainly be speaking to the Speaker of the House about whether it's acceptable for a foreign country's security services to rough up a member of Parliament on parliamentary grounds, I think that's totally unacceptable."
Speaker Lockwood Smith has confirmed he will investigate.
Dr Norman was following in the footsteps of late Green party co-leader Rod Donald, who also had a set-to with a Chinese delegation while protesting for Tibetan rights.