Senator Bishop has directly contradicted Mr Bullock's assertion he had not done a factional deal with the WA Left faction to secure first place on the Labor ticket for himself.

The deal, Senator Bishop claims, involved left wing United Voice WA powerbroker Dave Kelly securing a state seat and Senator Sue Lines taking over from former minister Chris Evans when he retired and created a casual vacancy in March 2013.

The accusation followed Mr Bullock's rejection on Friday of calls for him to stand aside as Labor's newest Senator for Western Australia. Mr Bullock said he was disappointed but "unsurprised" that the left wing United Voice union that helped him secure the top Senate spot in WA had since disowned him.

"That's the cost of standing for something," Mr Bullock said. "You will have friends and you will have opponents."

"I am as committed now as I was when I sought pre-selection."

In the days before the Senate re-run it was revealed Mr Bullock had given a speech last year ridiculing Senator Pratt’s sexuality, saying he did not always vote Labor and describing some members of his own party as “mad”.

Mr Bullock said Mr Kelly had supported him because he could trust Mr Bullock and that Mr Kelly's selection for a WA state seat was not a quid pro quo.

"He won the seat on merit," Mr Bullock said of Mr Kelly. "This is an odd thing to say in Labor Party circles but he won it on merit! Imagine that!"

Mr Bullock also denied a deal to ensure Senator Sue Lines filled a casual vacancy created by former minister Chris Evans had been struck.

But Senator Bishop said there was "a deliberate deal, and everyone in WA knew it".

"The deal was he [Bullock] got number one on the ticket and in exchange he and his union supported Sue Lines for the vacancy. Louise Pratt was sacrificed by the United Voice Left, by Dave Kelly, and in return he received a seat in State Parliament. And Carolyn Smith [the United Voice WA secretary who called on Mr Bullock to resign this week] is now protesting too much,'' he said.

"She [Smith] took over well prior to the September federal election and at any time in the last six months before the election could have undone the deal, was approached to do so, and refused to do so."

"Joe has never been shy about discussing his social views. Everyone knew he would attempt to give effect to those views."

Nor was Mr Bullock's support for the left wing Senator Sue Lines, a condition of his own pre-selection, he claimed.

"With regard to Sue [Lines], Chris Evans was in the seat before her. And to talk colloquially, he was the United Voice's senator.

A number of Labor MPs are blaming Mr Bullock for the party’s catastrophically low primary vote of 21 per cent. Labor is likely to win just one of the six Senate seats up for grabs in WA, with Senator Pratt missing out, according to ABC election analyst Antony Green.

Mr Bullock told Fairfax Media he had a disastrous campaign, but says at least the comments he made to the Christian group were "not deliberate" as they occurred in a question and answer session after his formal speech.

"In the last week of the campaign, golly I had a shocker," Mr Bullock said.

Mr Bullock acknowledged his right wing views alienated many in the Labor Party but he said his chief problem was his compulsion to tell the truth.

"My common failing is when confronted by a question I answer it."

It was in this truth-telling mode that Mr Bullock admitted on Friday that he did not always vote for Labor in the upper house, despite being Labor's number one - and probably only - senator elected in last weekend's WA Senate re-run election.

"I have from time to time voted number one for the Australian Christians and number two for the Labor Party," Mr Bullock said.

Follow us on Twitter