TV bosses have apologised after a reporter quit her job with a four-letter flourish during a live broadcast.

KTVA's Charlo Greene reported on the Alaska Cannabis Club - then revealed to viewers that she owned the medical marijuana business and intended to press for legalisation of recreational pot in the state.

"Everything you've heard is why I, the actual owner of the Alaska Cannabis Club, will be dedicating all my energy toward fighting for freedom and for fairness, which begins with legalising marijuana here in Alaska," Ms Greene, 26, said during Sunday night's newscast.

She then said: "F**k it I quit" and walked off camera.

KTVA news director Bert Rudman later apologised for Ms Greene's "inappropriate language" and said she had been sacked. And he apologised again early today, this time for Ms Greene's ethical lapses.

"She had a personal and business stake in the issue she was reporting, but did not disclose that interest to us," he said.

"At KTVA we strive to live up to the highest journalistic standards of fairness and transparency. Sunday's breach of those standards is unacceptable and cannot be tolerated."

Ms Greene is the professional name used by Charlene Egbe, and said she knew about a month ago that she would be leaving the way she did but no one else at the station knew anything about it.

Alaska voters will decide in the November election whether to join Washington state and Colorado in decriminalising pot.

Ms Greene said she did not believe the manner of her departure harmed her cause.

"Are we talking about it, or not, because of what I did? Period," she said. "It always goes back to the issue."

Ms Greene said she always fact-checked and was unbiased about the issue as a reporter.

"I'm passionate about doing my job, and at the time my job was being a journalist," she said.

Alaska business records indicate Charlene Egbe registered the Alaska Cannabis Club name on April 20, or 4-20. The number 420 has long been associated with marijuana, though its origins as shorthand for pot are unclear.

Taylor Bickford, a spokesman for a group backing the measure to legalise pot, said he hoped Alaska voters looked beyond Ms Greene's salty language.

"I hope that her language, which clearly was not appropriate for television, doesn't distract from the importance of her message," said Mr Bickford, of the Campaign to Regulate Marijuana Like Alcohol.

After voters approved the use of medical marijuana in 1998, the state of Alaska never set up dispensaries, forcing people to criminalise themselves to access pot, he said.

Passage of the initiative "would allow them to access the medicine they need", he said.

But a spokeswoman for opposition group Big Marijuana Big Mistake said it twice complained to KTVA management about what it claimed was Ms Greene's biased coverage of the ballot initiative.

"While we are frustrated with these actions, we are further disappointed by this distraction from what needs to be a full and honest debate about a dangerous initiative that will hurt Alaska's communities and kids," Kristina Woolston said.