Jim Justice, the Governor of West Virginia and currently a member of the Democratic Party, is set to switch allegiances to the Republican party as US President Donald Trump holds a rally in the state, according to multiple reports.

Justice won the heavy conservative state on the Democratic ticket even though Trump won West Virginia by a margin of 42 points. During the campaign, Justice controversially refused to endorse the Democratic candidate for president, Hillary Clinton.

West Virginia is home to many of the Appalachian mining communities Trump repeatedly said that his administration would save by rolling back environmental regulations.

Many have criticised this promise as unachievable, saying the lagging coal industry is more effected by a changing energy market.

The move will put particular strain on the state's Democratic Senator, Joe Manchin, who comes up for re-election in an increasingly conservative state that was once a stronghold for his party.

Justice has reportedly flitted between the parties before, having been a registered Democrat, Republican and Independent at different points, he campaigned as a conservative Democrat. With his move, the Democrats will only be left with 15 governors across the 50 states.

Justice, 66, is a billionaire coal mining and agriculture businessman born and raised in West Virginia. Known for his colourful character, earlier in the year Justice unveiled plate of bull excrement during a press conference to highlight his displeasure at a Republican state budget. He described it as "political bull you-know-what" before signing a veto.

In a similar move to Trump, the Associated Press reported that Justice handed over the daily running of his businesses to his chidren when he took office. He has also reportedly expressed concerns over health care in the state where thousands gained coverage under the expanded Medicaid program as part of the Obama-era Affordable Care Act.

Jim Justice
West Virginia Governor Jim Justice pictured in 2010 Scott Halleran/Getty Images