The England head coach, Jon Lewis, has said he has no intention of stepping down despite a disastrous Women’s Ashes tour in which England have lost five out of five matches played so far, saying his position was not up for debate.

“I don’t know if I need to defend my position,” he said. “I don’t employ myself. I’m really comfortable with the job that I’m doing. I’ll continue to work to develop this cricket team as best as I can until someone tells me that it’s not the right time for you to do this any more.”

He added that he felt he continued to enjoy the full confidence of the England and Wales Cricket Board. “I’m really excited about what the future holds for this team, and I feel like I’m the right person to coach it,” he said.

The ECB have confirmed that a full post-series review will take place after the Ashes concludes on 2 February. Any decision to remove Lewis before the conclusion of his current contact (which it is understood runs until at least November) would probably need to be agreed by a full meeting of the main ECB board.

That review will no doubt also include an appraisal of the captain, Heather Knight, who has led England for almost nine years without winning an Ashes series. Lewis refused to give any guarantees about her future. “After the tour, we’ll spend some time reflecting [on her role], and we’ll think about what the right thing is for the team further down the road,” he said.

Lewis seemed frustrated at times by the critical tone of the questioning, repeatedly saying that he feels the 10-0 scoreline is an unfair reflection of the actual gap between England and Australia, while rejecting claims that the England camp are refusing to properly confront the scale and nature of the Ashes defeat. “We’re really honest as a group,” he said. “The players are really open with each other.”

He added that he disapproved of Sophie Ecclestone’s refusal last week to do a TV interview with Alex Hartley – apparently due to Hartley’s recent criticism of the team’s fitness levels – and said he had been unaware of Ecclestone’s decision until after the fact. “I would have liked her to do the interview,” he said.

Hartley has since said that she feels she has been “given the cold shoulder” by the England team, but Lewis denied that a siege mentality had developed within the dressing room. “We’ve got a really healthy respect for the media,” he said. “I don’t think there’s any issues.”

However, he once again vociferously denied Hartley’s suggestion that England are experiencing issues with fitness. He did acknowledge that Australia are clearly the fitter team, but – bizarrely – appeared to blame this on what he labelled “cultural difference”, including the warmer weather.

“I walked from Bondi to Coogee last Sunday evening and pretty much every Australian in the eastern suburbs is in the water, doing Surf Lifesaver, playing touch rugby. Our talent pool at the moment is small, and I definitely think Australia have an advantage in terms of athleticism,” he said.

England play the final T20 of the series on Saturday in Adelaide, followed by a one-off pink-ball Test at the Melbourne Cricket Ground starting on 30 January. The Australia batter Grace Harris told the BBC on Thursday that the hosts would be aiming for a 16-0 whitewash, but Lewis said England would be working hard to deny them that goal.

“I think Grace probably did my job for me,” Lewis said. “I’ll give her a pat on the back when I see her. The players are really aware that they need to win some cricket matches. They’re working incredibly hard to do that.”