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.

The former Victorian 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.   

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Senator Madigan 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.”

The DLP has left me, I haven’t left the DLP.

Senator Madigan said he had become the victim of a DLP attack after hiring a party-recommended office manager.

The manager had sent an email to the Liberal Party asking about preselection in the November Victorian state election two weeks after being hired.

“That person systematically ran a campaign of disinformation and disharmony in my office,” Senator Madigan said, adding confidential information was leaked and lies were told.

Senator Madigan is expected to table a set of documents relating to his reasons for quitting later on Thursday.

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

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

“My values haven’t changed, my outlook of the world hasn’t changed.”

He declined to say whether he would seek re-election in 2016 and rejected suggestions he was forming a voting bloc with other crossbenchers.

Independent senator Nick Xenophon, who has worked closely with Senator Madigan, said it would remain a “loose alliance”.

He said being “free of party directives” would enable Senator Madigan to better represent Victoria.

“That’s probably a good thing for him politically,” Senator Xenophon said.

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

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

“We will work with him as an independent senator just as we worked with him as a DLP senator.”

– AAP