Pete Buttigieg speaks at a campaign event on December 8, 2019 in Washington, Iowa. (Win McNamee/Getty)

Democratic candidate Pete Buttigieg is soaring in popularity in the Republican-dominated state of Arizona, with a new poll putting him neck-and-neck with Donald Trump.

Alongside his fellow Democratic hopeful Joe Biden, Buttigieg is in a statistical dead heat with Trump, suggesting that even staunch Republicans in Arizona are beginning to turn their backs on the party.

Buttigieg has 43 per cent support, compared to Biden’s 44 per cent and Trump’s 46 per cent, the latest poll shows. This represents a decrease in support for Biden, who led Trump 49 percent to 44 percent in the state based on a May poll.

The South Bend, Indiana mayor however, has increased his support by six points, disproving the critics who predicted his sexuality meant he would struggle to make inroads in strongly conservative states.

Buttigieg, 37, has also carved out a lead in Iowa after an “aggressive” campaign trail aimed at the rural midwestern state’s older, moderate voters in small towns.

Last month he shot ahead with 25 per cent support – a nine point lead over Elizabeth Warren, who is the next highest Democratic candidate – in Iowa.

Only 30 per cent of respondents said that their minds are made up and a lot could change before the Iowa caucuses next February, but if Buttigieg’s lead continues he could stand a real chance against Biden and Warren.

Although Iowa’s demographics aren’t representative of the rest of the country, the state is significant as it’s often thought to set general trends for presidential elections.

It’s not all been plain sailing for Buttigieg though – he attracted some scorn last week after a picture of him volunteering for the notoriously ‘homophobic’ charity Salvation Army was circulated online.

And an internal focus group recently revealed findings that suggest Buttigieg’s sexuality could be “a barrier” for many black voters, particularly with black men who were “deeply uncomfortable even discussing it” in the study.

The report concluded: “Their preference is for his sexuality to not be front and centre.”