The opposition leader, Sussan Ley, does not believe Andrew Hastie is after her job and has subtly rebuffed his claims that immigration levels are making Australians feel like “strangers in our own home”.

Ley declined to endorse Hastie’s comment when asked about it on Monday, instead blaming the government for not building the infrastructure needed to cope with a growing population.

“You see for yourself how the lack of infrastructure is contributing to the struggles that people are facing every day,” she told reporters in Albury.

“This has nothing to do with any migrant or migrant community, but this is a reprehensible failure of government to put the infrastructure and services in place that Australians deserve.”

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Ley refused to be drawn on whether Hastie’s remarks were divisive or unhelpful for the Liberal party as it conducts a post-election review of its policy agenda.

“I’m very confident that all of my colleagues are expressing strongly held views, and they do that in many ways,” she said.

On Monday, she faced questions for the first time about Hastie’s recent string of provocative policy statements, which have prompted speculation the shadow home affairs minister is positioning himself for a future leadership challenge.

Hastie – who has repeatedly declared his aspirations to one day lead the party – last week said he supported Ley and anyone suggesting otherwise was “being mischievous”.

Asked on Monday if she was worried the former soldier was angling for her job, Ley told reporters: “No, I’m not.”

In his most recent policy intervention, the Western Australian MP used social media to warn that the Liberal party could “die” as a political movement if it did not commit to curb net overseas migration, which he blamed for the housing crisis.

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Hastie claimed the rate of net overseas migration, which has subsided since a post-pandemic surge, was making Australians start to “feel like strangers in our own home”.

The line echoed the former UK MP Enoch Powell’s infamous “rivers of blood speech” in 1968, in which he imagined a future multicultural Britain where the white population “found themselves made strangers in their own country”.

The UK prime minister, Keir Starmer, used a similar “island of strangers” line in a speech in June – for which he later expressed regret.

Hastie’s remarks have one again exposed the divisions inside the party, with some MPs privately frustrated at his freelancing while others, such as Jacinta Nampijinpa Price, openly praise his outspokenness.