Carrie Lam Cheng Yuet-ngor has sought to downplay her eyebrow-raising pledge that she would resign as chief executive if the mainstream view was against her, as her campaign team mulls a strategy shift before she returns to debate mode on Sunday.

In a bid to clarify her unexpected remarks the night before during a televised debate with two other chief executive candidates, the former chief secretary on Wednesday tried to draw a distinction between "mainstream opinion" and "personal popularity ratings".

Lam said she would take into account mainstream opinion if elected to the city's top post on March 26, rather than fluctuating popularity ratings.

"I was not talking about personal popularity ratings," she said. "They go up and down."

"Just in case, if there is one single issue where the mainstream view of the Hong Kong people is contradictory to the faithful and truthful execution of the Basic Law, then the chief executive, in my view, should resign," Lam told the media.

"[That's] because he or she would not be able to discharge that constitutional function enshrined in the Basic Law while respecting the mainstream view of the people."

She however sidestepped questions on whether she would quit if confronted with huge protests from the drafting of the controversial national security legislation.

Meanwhile Lam's arch rival in the race, former financial ­secretary John Tsang Chun-wah, has widened his lead over her to more than 17 percentage points, according to the latest survey commissioned by the South China Morning Post.

On Tuesday, Lam was asked by an audience at the debate what she would do if the views of Hongkongers differed from hers. Lam had said she would resign if "mainstream opinion made me no longer able to continue the job as chief executive".

On Wednesday, Tsang expressed doubts over her clarification of the remark. "She is sometimes talking about resigning, and sometimes talking about not resigning. This is rather negative, because one should persevere even in the most difficult of circumstances," he said.

A member of her campaign team, reviewing her performance on Tuesday, said she could be more articulate in Sunday's debate – the last chance for the candidates to cross swords.

"She should relax her pace and spend more time elaborating her governance visions and policies," he said.

Some 1,194 members of the Election Committee will choose the next chief executive from three candidates – Lam, Tsang and retired judge Woo Kwok-hing – on March 26.

Lam's clarification came after another verbal stumble last weekend when she was slammed for likening online comments critical of her and her supporters to "white terror".

Former security minister Ambrose Lee Siu-kwong, now a local deputy to the National People's Congress, said he did not watch the debate, but he took the chance to take a swipe at Tsang.

Lam had named supporter and popular actress Josephine Siao – who has a hearing disability – as a victim of "white terror", but Tsang had argued that "online comments are not white terror", adding freedom of speech was one of the city's core values.

Lee said of Tsang's retort: "I am very unhappy to see [him] tolerate cyberbullying of a disabled actress who is well respected by Hongkongers." Lee had also earlier indicated his preference for Lam.

But another National People's Congress deputy, Michael Tien Puk-sun from the New People's Party, described Lam's performance in the last debate as "disappointing". He added that he was inclined to vote for Tsang.

"I'm surprised to hear Lam saying she would resign if she became too unpopular," Tien said. He noted that a leader should not easily buckle under pressure, and claimed that Lam also lacked political sensitivity.