The Northern Territory’s chief minister has said he was “horrified” to learn his sports minister had sent sexually explicit videos to a female constituent.

Nathan Barrett resigned from the Country Liberals cabinet on Saturday after admitting he sent two videos of himself masturbating to a woman, which she told News Corp Australia were unsolicited.

The chief minister, Adam Giles, said he was sorry to see Barrett quit his portfolios of assistant treasurer, sport and recreation and young territorians, “but quite frankly he had to go, there was no other choice”.

Upon reading the news, he said he was “horrified to see what has been done”.

“I don’t want a minister in the NT parliament who behaves like this,” Giles told reporters.

The scandal-plagued government faces an election in less than three months, and Giles said it was up to the party to decide whether Mr Barrett would remain preselected for the seat of Blain, in the Country Liberals heartland of Palmerston.

Mr Giles would not comment on allegations that Mr Barrett offered the woman a job if he became treasurer after the 27 August poll.

“He manipulated me ... He did use his power to influence me. I was vulnerable,” the woman told News Corp Australia.

In a statement, Barrett apologised “to the woman with whom I was involved for a short period”, as well as to his family, electorate, and colleagues.

“I am very disappointed with my actions; I endeavour to represent my community effectively and improve the lives of the people of Blain and the entire NT,” he said.

“I did not live up to these standards when I engaged in an inappropriate relationship. While this is essentially a private matter that my wife and I have been working through for some time, I unreservedly apologise.”

Giles said the matter was a perfect example of societal acceptance of sexual harassment and abuse of women that he was hoping to change.

He said Barrett was “not in a good space” and that he was seriously concerned about his mental health, and had urged him to spend time with his family and to seek counselling.

Giles said he would take over Barrett’s portfolios for the short term, possibly until the election.

Barrett is the second frontbencher to resign this year, following that of former deputy chief minister Willem Westra van Holthe, who was forced to stand down in February after it was revealed he had planned to invest more than $500,000 with a subsidiary of Vietnamese company CT Group, which was seeking to develop a 10,000-hectare dragon fruit farm in the top end.

He was also in a relationship with an employee of the company at the time.