Australia's new Senate could sit before legal challenges to the election result in Western Australia are determined, a High Court justice says.
The High Court, sitting as the Court of Disputed Returns, is hearing three separate petitions about the result of the fifth and sixth Senate places in WA.
Justice Kenneth Hayne on Thursday said the matters may not be settled before the new Senate commences sitting in July.
"I cannot dismiss the possibility that ... after the first of July the Senate may not be properly constituted," he said.
"That possibility is best avoided."
The result in WA has already been the subject of a recount and an investigation by former Australian Federal Police chief Mick Keelty after 1370 votes went missing.
In the initial count, the final two WA Senate places went to Zhenya Wang of the Palmer United Party (PUP) and Labor's Louise Pratt.
But in the recount, without the missing votes, Wayne Dropulich of the Australian Sports Party and the Greens' Scott Ludlam were elected.
The Australian Electoral Commission (AEC) has sought a fresh election, while PUP and Labor have launched separate actions seeking the first vote count be declared the official result.
Lawyers for the AEC told the directions hearing in Melbourne that a new election must follow, as the two counts could not be relied upon.
Justice Hayne proposed that a hearing be held before a single justice in January to determine questions of law, and if necessary the full bench of the High Court to decide any remaining issues.
The matter was adjourned until Friday for a further directions hearing.
After his investigation, Mr Keelty concluded there was a "culture of complacency" in the WA office of the AEC.
Officials also failed to assure themselves of the "political neutrality" of people responsible for the transport and storage of ballots, parcels, boxes and pallets, he said.
He said a fresh election would cost taxpayers $13 million.
