Bill Shorten has sidestepped claims his personal unpopularity was a drag at the 2016 federal election, insisting Labor defied all expectations by coming close to victory.
The Seven Network has reported an internal review of the ALP's campaign found Mr Shorten hindered the opposition's success.
The report, written by 18 senior Labor members, has not been publicly released and is understood to have only been read under strict conditions by a handful of ALP national executive members in August.
Mr Shorten says the party's performance had surprised "all the experts" and he had learned valuable lessons from the campaign.
"People didn't give Labor any chance when Turnbull took over ... that's it, he will be there for a decade," Mr Shorten told reporters in Perth on Friday.
"The point is people are not interested in the personalities but interested in the action and substance. Labor put together policies for the last elections, 100 positive policies.
"We campaigned on them and got close."
Prime Minister Malcolm Turnbull was reluctant to comment when asked about the ALP report.
"The important thing is that we won the election and look at how much we've done with a one-seat majority in the House of Representatives and nowhere near a majority in the Senate," he told the Seven Network.
Labor won a net 14 seats at the election, almost defeating the coalition after one term in government.
The party's campaign focused heavily on policy, while the coalition sought to take advantage of Mr Turnbull's personal popularity after ousting the unpopular Tony Abbott in September 2015.
The Australian reported last week that Labor senator Jenny McAllister briefed the national executive on the report's statistical analysis and executive members held a broad discussion about the campaign.
