The Democratic Labour Party has been sent into a spin as its only senator John Madigan quit amid claims of spying in his office.

Crossbench senator John Madigan has blamed a “cancer of political intrigue” for his decision to quit the Democratic Labour Party (DLP) and become an independent.

Senator Madigan on Thursday took the extraordinary step of tabling in parliament emails sent by his office manager, Victorian DLP executive member Rachael Carling-Jenkins, to the DLP’s Victorian secretary Michael Murphy.

He accused Dr Carling-Jenkins – who resigned in August – of being planted in his office by the DLP to undermine him.

In one of the emails, Dr Carling-Jenkins describes herself to Mr Murphy as “spy of the month” and signs off as “Mata (Hari, the notorious spy)”.

In a bizarre twist, in February she emailed the Liberal Party in Victoria seeking advice on getting preselection for the state election despite not being a member.

Senator Madigan, a former blacksmith, was elected in 2010 becoming the first DLP senator in almost four decades.

Ironically, his party, which is riven with factionalism, was itself formed from a devastating split in the Australian Labor Party in 1955 and has about 1700 members nationally.

The senator told parliament on Thursday his party had become infected by the “cancer of political intrigue” which was proving to be a distraction.

“It has become apparent to me that the DLP’s own worst enemies are within its own ranks,” he said.

“I’ve witnessed first-hand attempts by those in the party to assume power at any means even if it means the very destruction of the party itself.”

Senator Madigan said his office manager had run a “campaign of disinformation and disharmony in my office”.

Speaking to reporters later, Senator Madigan said he stood by the values of the DLP.

“The DLP has left me. I haven’t left the DLP,” he said.

He declined to say whether he would seek re-election in 2016.

However, later on Thursday evening he said he would definitely recontest his seat.

“I’m happy to stand before the people and let the people decide,” he told ABC television.

DLP national president Paul Funnell said Senator Madigan should either surrender the seat to a DLP member or reconcile with the party.

“We put our trust in him and this is how he has repaid us,” Mr Funnell told AAP.

Senator Madigan said he wouldn’t be giving up his seat.

“I was the person whose name was on the ballot,” he said.

“I’m at one with the people who believe in the true ethos of the DLP.”

Mr Funnell said Senator Madigan should remember the “80-year-olds who stood at polling booths on cold days” and got him elected.

A teleconference of the DLP national executive left the matter in the hands of the Victorian branch.

Mr Murphy said Dr Carling-Jenkins had been put in the office “to work for the best interests of John and the party”, after Senator Madigan had sought help and endorsed her for the job.

Independent senator Nick Xenophon, who has worked closely with Senator Madigan, said being “free of party directives” would enable Senator Madigan to better represent Victoria.

Opposition Leader Bill Shorten said a small party had just become smaller.

“I don’t know what on earth is going on within the DLP,” he told reporters.