Bill English's diplomatic protection squad kicked into gear at a Blenheim cafe on Tuesday morning when Labour's local candidate arrived unannounced and paced towards him.

Janette Walker, who is standing for Labour in the Kaikōura seat, caused dramatic scenes at the BV Deli, which started with her confronting National's local board chairman about her signs being damaged.

She sat down at Tim Leslie's table and asked about a number of signs at the airport being ripped down last night, before accusing him of being behind it.

"If you go public with those allegations, I'll f*****g sue you," he replied.

"I did not touch your signs. I'm moving away from the cameras," he said before leaving the cafe when Newshub started filming.

Another National supporter then confronted Ms Walker, claiming her allegations were defamatory. He also left the cafe.

Ms Walker then paced towards Mr English, prompting his personal police to rush after her. He was quickly ushered out the back of the cafe.

"Good luck with the campaign," Mr English curtly said as he passed her.

Ms Walker said the signs were ripped down last night, on the eve of Mr English flying in, and claimed it was more than just a coincidence.

"I'm pretty certain it was National people", she said. "They were prominent. They were on the airport route, so I presume they took them down because they didn't want Bill English to drive past Labour signs."

Ms Walker said she replaced the signs at 7am on Tuesday.

"I farm 2000 acres on my own, so I know how to punch back," she said. "They wanna take my signs down? I'll put more up."

National rejects the allegations.

Newshub.