Documents obtained by The Express show Mr Marshall, the Nationals candidate for Northern Tablelands, was a member of both parties between 2001 and 2003.

But Labor branch members raised concerns about his membership because he was also working for then independent Tamworth MP Peter Draper.

Mr Marshall subsequently let his Labor membership lapse. Former Tamworth based Labor MLC Christine Robertson claimed Mr Marshall was working against the Labor Party during his time as Mr Draper’s staffer.

“Adam was busy playing everybody,” she said.

Mr Marshall said he recalled joining Labor in 2000, but jumped ship to the Nationals 12 months later after becoming disillusioned with the ALP.

“On May 25 there will be Nationals under my name, not Labor, something I’m very proud of,” he said. 

“I find it interesting that Labor’s trying to smear me by saying I used to be one of them.” But Labor Party records show Mr Marshall first joined the ALP in December 2001, renewing his membership in 2002.

He last paid membership dues in November 2003, according to the records.

Country Labor organiser Courtney Roche said Mr Marshall would have been considered a member of the party until 2004, after which his membership lapsed.

The party records show a recommendation that Mr Marshall’s membership not be renewed because “of his National and Liberal Party links through Gunnedah Council”.

It also mentions concerns about his work with Mr Draper.

Northern Tablelands Country Labor candidate Herman Beyersdorf said he was not surprised by Mr Marshall’s past membership.

“It seems to be almost a familiar trajectory - Labor, independent, National Party - and I see it as a transition from idealistic youth to calculating politician,” he said.

NSW Nationals state director Ben Franklin said he was “not remotely concerned” about Mr Marshall’s earlier membership of the Labor Party.

“We were aware that he was a member of Young Labor and totally understand that everyone makes mistakes,” he said.

“He was a young person quite interested in politics trying to figure out the best path for himself.”