The chaplain for the US House of Representatives has been forced to step down amid accusations he was 'aligned with Democrats'.

Rev Patrick Conroy, a Catholic priest who has worked as House chaplain since 2011, was asked to quit by Speaker Paul Ryan, his resignation revealed.

'As you have requested, I hereby offer my resignation as the 60th Chaplain of the United States House of Representatives,' the letter, dated April 15 and obtained by The Hill, read.

Four sources told the news site that Conroy had been told to retire or be forced out and one said he was pushed 'because Republicans thought he was aligned with Democrats', according to The Hill.

House chaplains are supposed to be nonpartisan but the decision seems to have been made on political grounds, according to The Hill's sources.

There are suggestions Republicans were unhappy because of a prayer on the House floor that was perceived as critical of the GOP tax bill.

'May all members be mindful that the institutions and structures of our great nation guarantee the opportunities that have allowed some to achieve great success, while others continue to struggle,' Conroy said at the time. 'May their efforts these days guarantee that there are not winners and losers under new tax laws, but benefits balanced and shared by all Americans.'