Former Devonport mayor Steve Martin has been formally cleared to replace Jacqui Lambie in the senate after she failed in her apparent bid to expel him from her party.
Australia's highest court on Friday ruled Mr Martin eligible to replace Ms Lambie, ruling that she left her run too late to expel him from the Jacqui Lambie Network.
The High Court decision was made despite reports Mr Martin had been dumped from the JLN this week over a "lack of commitment".
In a letter released to media on Wednesday, Ms Lambie said Mr Martin had broken the values of "mateship, respect and integrity" by terminating staff members he said he would retain.
But Justice Geoffrey Nettle said Ms Lambie should have brought forward any challenge to Mr Martin's election months ago.
"There is no appearance (in court) on behalf of Ms Lambie, or any evidence in support of what is said to have happened in the press," Justice Nettle told the court, sitting in Melbourne.
"It has not been established that Mr Martin has ceased to be a member of the Jacqui Lambie Network party.
"It is declared that Steve Martin be duly elected as a senator for the state of Tasmania."
Mr Martin was appointed after an electoral recount following Ms Lambie's forced resignation when she learned she was a dual British citizen.
But he ignored her pleas to step aside to allow her to reclaim her senate seat after renouncing her citizenship.
Mr Martin has vowed to "hustle" in his new role to help his state of Tasmania, and said he will be meeting the prime minister next week.
"I'll be dealing with each issue on its merits and where we can get a win for Tasmania, I'm certainly willing to compromise and to wheel and deal and to hustle," he told AAP on Friday.
The High Court also ordered that former Liberal minister Richard Colbeck replace the party's ousted speaker Stephen Parry, who was disqualified over dual citizenship.
Mr Martin and Mr Colbeck are expected to be sworn into the Senate in Canberra on Monday.
Australian Associated Press