Karie Murphy says report has not proved allegations of voting irregularities during her bid to become parliamentary candidate

The activist whose failed campaign to become Labour's parliamentary candidate in Falkirk sparked Ed Miliband's radical reorganisation of the party's union links has condemned an internal investigation into voting irregularities in the constituency.

In her first statement since she was forced into standing down in the central Scotland seat, Karie Murphy said the report had not proven any allegations of voting irregularities levelled against her. On Monday night the Guardian published the full investigation online for the first time.

Disclosure of the internal report, commissioned by the party's national executive committee in May, comes as Labour's hierarchy prepares for a crucial NEC meeting on Tuesday that is expected to redefine its historic relationship with the unions.

The report cited "evidence that members were pressured into completing direct debit forms" by activists from trade union Unite, as they sought the nomination of Murphy. One new recruit, Lorraine Kane, was said to have told a Labour investigator that Murphy had put her under pressure to sign one of the forms.

But those who are subjects of the report dispute what has emerged of its findings. In an emailed statement, Murphy, a friend of Unite general secretary Len McCluskey, dismissed the claims: "NONE of the allegations were supported by evidence. I didn't recruit the Kanes or ask them to sign recruitment forms."

In September, Kane clarified her statement in an affidavit, suggesting she had never meant to allege any wrongdoing.

The report raises questions over the Labour leader's response last summer when Murphy and Stevie Deans, a leading Unite figure and the then Falkirk constituency party chairman, were suspended from the party and police were invited to launch a criminal inquiry. Miliband has refused to release the report despite saying there was evidence of "a politics of the machine, a politics hated" in Falkirk.

He has faced repeated demands to release it from Tom Watson, the MP whose office employs Murphy and who resigned as Labour's campaign co-ordinator over the Falkirk affair, as well as the local party's executive.

At no point were any of Labour's allegations formally put to Murphy or Deans. Friends of both said the report was inaccurate and damaging.

Both were later reinstated to the party but with their reputations shredded by leaks to the media.

The report shows that as candidates including Murphy recruited increasing numbers in Falkirk, swelling the membership to nearly 300 by May 2013, the party became reliant upon the union to tell them who had joined and when.

It lists eight conclusions in its executive summary, which were widely leaked to national newspapers. But the Guardian's own analysis of the report can only find evidence to fully support two of these critical conclusions. The others appear overstated at best.

The 20-page report entitled Falkirk Membership Inquiry and marked "strictly private and confidential", was written by an unnamed author or authors last June. The seat, which has a majority of 7,800, had been vacated by Eric Joyce, the Blairite MP who stood down after taking part in a brawl in a House of Commons bar.

The report reveals Labour's fears over the the threat from Scottish Nationalists, noting that "this seat is targeted by the SNP and should a by-election be called following Joyce's most recent arrest, the contest could be highly marginal."

There is no doubt that Unite had been actively recruiting members across Falkirk to Labour, many of whom had been asked to sign up under the "union join" scheme – an agreement between Labour and unions which allowed union members to be recruited to the party. In exchange for having their first year of fees paid for by the union, the new members would sign a direct debit to the party for at least a year.

Linda Gow, a Falkirk councillor, former care home worker and another prospective candidate, first raised questions over Unite's recruitment drive in March, the report said. She wrote a letter alleging that members of two families – the Kanes and the Millars – had been signed up under the scheme without their knowledge.

Investigators compiling the report noted that the party has a muddled system of processing new members. "Some of the forms submitted by Unite were disputed … This was due to some confusion over the rules agreed with TULO [Trade Union and Labour party Liason Organisation] in accepting union application forms," the report states.

Matthew Jackson, the party's head of member services, submitted evidence saying on one occasion a batch of around 40 application forms arrived with a letter from McCluskey saying that Watson had said they were "OK". "The Labour and Unite general secretaries agreed that these would be processed," the report said.

Jane Shaw, a Labour compliance officer, was asked to take on the inquiry by meeting a sample of 31 people who were recruited. She was accompanied by a Scottish Labour activist Hannah Lister. However, they were able to contact just five households.

They did not investigate any of the 11 people whose joining fees had been paid with a single cheque by Gregor Poynton, a Blairite prospective candidate. Poynton has said that he behaved properly and kept the Labour party fully informed of payments that he made.

Shaw, accompanied by Lister, did interview three members of the Kane family and wrote in the report that their recruitment by Deans may have breached Labour rules.

The investigators' final visit in Falkirk resulted in a tense stand off with Deans. Shaw and Lister knocked on the door of Brenda McDermott and her parents, Catherine and Peter McDermott, for a pre-arranged meeting about their membership of the party.

"The door was answered by a man who later identified himself as Stephen Deans, chair of Falkirk," the report says. Shaw asked to speak to Brenda McDermott but was told by Deans that she had felt "pressurised" by the two investigators. Shaw said this was not her intention.

Deans pointed out that Shaw had met a number of his relatives and friends – Lorraine Kane, who is his wife's aunt, and Jim Millar, one of his close friends.

Shaw assured him it was not her intention to target his friends and relations and "then asked if there was anyone else she should not call upon," the report said.

Watson is understood to have never seen the report, was not asked to contribute to it and has never verified any membership applications for Falkirk or any other constituency.

A solicitor for Deans said: "Our client has been completely exonerated on two separate occasions by the police and separately by the Labour party. There is no case to answer as has been clearly shown."

Lister said she had no part in determining who was to be interviewed or the report's conclusions.

A Labour spokesman said: "We have selected a candidate in the constituency. The important thing now for the people of Falkirk is that we concentrate on getting a Labour MP elected to represent them."

Unite did not respond to a request for a comment.