Downer 'comfortable' with Mayo campaign

Liberal Mayo by-election candidate Georgina Downer says she is "very comfortable" with her campaign, despite recent polls placing her well behind Centre Alliance candidate Rebekha Sharkie.

Sharkie leads Downer 58-42 per cent on a two-party preferred basis, according to a ReachTEL poll of 1031 Mayo voters commissioned by the Australia Institute.

"There is a real feel in the electorate of what a Shorten Labor government could lead to in this country, and it is quite clear that there is an alliance being created here with my opponent Rebekha Sharkie and the Labor Party," Ms Downer told reporters in Yankalilla, south of Adelaide, on Wednesday.

Ms Sharkie won the seat at the 2016 election but was forced to resign in May over issues of dual citizenship.

Ms Downer was selected as the Liberal Party's candidate, but has faced criticism throughout the campaign after spending the last 20 years away from the electorate.

Her father, Alexander Downer, held the seat for 24 years until his 2008 retirement.

The younger Downer was joined by Senator Simon Birmingham on the campaign trail on Wednesday - the latest of political heavyweights including Prime Minister Malcolm Turnbull and Senator Michaelia Cash to visit the electorate.

She was also forced to explain her social media strategy, after her Twitter account was deactivated and comments removed from her Facebook page.

"I'm not longer active on Twitter because, quite frankly, Twitter is not the place where we, as political candidates, find it's best to engage with our communities," she said.

"I use Facebook as my medium for engagement with people in Mayo, and where there are comments that are unacceptable, or trolls... then sure, we don't think they are fruitful for political debates and commentary."