The issue is apparently so concerning to US politicians that it made its way to the House of Representative's House Judiciary Committee earlier this month.

Congress has held two hearings on the issue, exploring so-called "filtering" practices of major social media companies and policies surrounding the removal of content.

Republican legislators repeatedly questioned why pro-Trump personalities like vloggers Diamond & Silk and conservative publications like Gateway Pundit were seemingly being censored.

Several right-wing commentators have accused Twitter of shadow banning them, including US trader and outspoken Trump fan Ernie Varitimos.

Self-described financier and conservative political commentator Jacob Wohl went further, questioning whether the social media platform was preventing people from following him.

On Friday, Twitter denied that it was purposely obscuring some profiles but admitted that it may be a side effect of the platform's attempts to improve the quality of discussions.

Twitter's product lead Kayvon Beykpour said that the company started adopting machine learning and "behavioural signals" in May to minimise the prominence of users that "detract from healthy public conversation".

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"This approach looks at account behaviour & interactions with other accounts that violate our rules," he said.

The "behavioural ranking" doesn’t make judgements based on political views or the substance of tweets, he said.

However, he admitted that some bugs in the ranking technology were preventing some accounts from appearing in the search drop-down menu.

"We’re making a change today that will improve this," he said.

Rather than indicate an anti-Republican conspiracy, Beykpour's explanation suggests that those users who are being seemingly sidelined interact with spurious users or share misinformation more than others.

Twitter's new system "seems less about suppressing conservative viewpoints and more about minimising controversial figures whose primary tactic is to stoke outrage through heavy slant or outright distortion," New York magazine writer Brian Feldman opined.

"It’s well-established that right-wing media and personalities hew further to the right, and are consequently more likely than their left-wing counterparts to interact with fringe accounts (the kind of signal that would indicate to Twitter’s algorithm that an account is a troll or harasser), if not actually spread falsehoods and sensationalised outrage."

Twitter shares fell 4 per cent in afternoon trading on Thursday in the US.