Footage has emerged showing government MP Natasha Griggs confronting a union member in the street demanding she stop filming her and knocking the phone to the ground.

In an incident that's been labelled "aggressive", Ms Griggs walks up to the filmer repeating "don't video me" before the screen goes black for a few seconds while the phone is on the ground.

Maritime Union of Australia's Northern Territory branch secretary Thomas Mayor witnessed the incident at the NT's Palmerston Night Markets while handing out flyers about seafarers jobs.

He says Ms Griggs hit the phone out of the union member's hand.

"She's lying when she reckons the woman dropped it," he told AAP on Saturday.

"It was aggressive."

Unionists can be heard yelling "shame" after the incident.

Ms Griggs insists she put up her hand to block the footage being taken by the "union operative" after she refused to stop filming.

At that point the unionist dropped the phone to the ground and another started chanting, she said.

The MP labelled the incident "nothing more than another union stunt".

"I will not be intimidated by the unions nor should the people of Darwin and Palmerston," she said in a statement to AAP on Saturday.

Labor is hopeful it can reclaim Ms Griggs' marginally held seat of Solomon in the Northern Territory.

The Country Liberal Party MP won the electorate from Labor in 2010 and retained it by 1.4 per cent last election.