They claim a campaign volunteer was brought to tears after two men verbally abused her at Darwin's early voting centre on Saturday.

The men were allegedly wearing union shirts and holding an Australian Labor Party placard when they berated the 26-year-old women.

"(She) was quite shaken," CLP president Ron Kelly told AAP on Monday.

"She felt threatened, harassed and bullied. It's reprehensible behaviour."

The matter has been referred to police and the NT Electoral Commission.

It follows another alleged campaign incident on Friday night when a well-known Darwin businessman and CLP donor was assaulted outside a city hotel.

"I am happy for people to have passion and get involved in the democratic process and have their say, but there's a line you just can't cross," Mr Kelly said.

"With these incidents, the line has definitely been crossed."

Territory Labor and Chief Minister Michael Gunner's office have been contacted for comment.

The commission is also investigating, with the help of Facebook, social media posts attacking CLP Fannie Bay candidate Tracey Hayes.

"Vile Facebook trolling," Mr Kelly said.

Meanwhile, almost 30 per cent of eligible Top End voters have cast their vote as of Monday morning.

It equates to 40,348 votes out of the 141,225 people on the electoral roll, the electoral commission says.

The official polling day is Saturday

Australian Associated Press