Former One Nation leader Pauline Hanson will lodge papers in the Supreme Court challenging the vote count at the New South Wales election.

Her lawyer has issued a statement saying the papers will be lodged in the Court of Disputed Returns tomorrow.

Last month Ms Hanson claimed the preferences were not distributed fairly and raised concerns about the preference system used by the NSW Electoral Commission.

Nationals candidate Sarah Johnston, who took the 21st and last spot up for grabs in the NSW Legislative Council, was 1,306 votes ahead of the former federal MP.

Before preferences, Ms Hanson led the Nationals by 7,540 votes and the Greens - which took the 20th spot - by 15,470.

Ms Hanson was also upset by reports a scrutineer had discovered votes for her in a bundle of blank votes.

"It's not just about Pauline Hanson," the former federal MP for the Queensland seat of Oxley said on April 13.

"We need to make sure that this is a fair and just election. I just don't feel that this election was conducted this way."

- ABC/AAP