The Parliamentary Budget Office has rejected reports it has produced new modelling of Labor’s tax policies, seriously undermining the latest effort from Scott Morrison to discredit the opposition.

News Corp papers the Daily Telegraph, Herald Sun and the Courier-Mail published much-hyped stories on Monday claiming “new modelling” from the PBO and Treasury showed Labor’s policies would increase the tax burden on Australian households by more than $100bn.

The treasurer jumped on the stories on Monday, telling Sky News: “There is a tax winter coming under Bill Shorten if he ever becomes prime minister.”

Morrison’s office had dropped the story to the newspapers on Sunday afternoon, to be published on Monday morning, and told their journalists the new figures came from “independent modelling by the PBO and Treasury”.

But Jenny Wilkinson, the parliamentary budget officer, has dismissed the suggestion that the PBO was involved in producing Morrison’s “new modelling”.

“References in the media this morning to modelling being released today by the Parliamentary Budget Office (PBO) are incorrect,” she said in a statement. “The analysis reported in the media this morning was not conducted by the PBO.”

Wilkinson said the PBO had released a post-election report on 5 August 2016, containing costings of all of the policies that the major parliamentary parties took to the last election.

Morrison later admitted on Sky News that the new figures were not from new PBO modelling but were an extrapolation from some of the PBO’s modelling from last year. He also did not say his figures had failed to take into account Labor’s promised tax cuts.

“Of course there will be further work done on these things but the point is that Labor wants to completely take the speed limits off tax in our economy,” he said.

The shadow treasurer, Chris Bowen, has slammed Morrison for politicising the PBO. “Not one number is correct, nor is it from the PBO, and Labor condemns the blatant politicisation of the independent Parliamentary Budget Office,” Bowen said.

“The number-one mistake in Scott Morrison’s latest problem with numbers is failing to mention Labor cutting income taxes for low- and middle-income earners. In fact, combined with the extension of the budget repair levy, the budget is better off by $4.3bn over the medium term.

“Here we are barely a year into the parliamentary term and the treasurer of Australia is reduced to making up stuff and pushing negativity instead of outlining a plan for jobs and increasing wages for low- and middle-income Australians.”

Last year Morrison was repeatedly criticised for promoting questionable modelling to try to discredit Labor’s policies.

In March 2016 he seized on modelling by the consultancy firm BIS Shrapnel (now called BIS Oxford Economics) that “predicted” $19bn would be wiped from Australia’s gross domestic product and rental prices would jump by 10% if negative gearing was abolished on established dwellings.

He claimed the modelling was “an indictment on Labor’s policy” and demonstrated that “they just haven’t done their homework on this”.

But a BIS Shrapnel associate director, Kim Hawtrey, later told journalists the modelling had been conducted “well before” Labor’s policy had been announced, so it wasn’t modelling of Labor’s plans at all.

In May last year the advisory firm MacroPlan Dimasi prepared modelling designed to discredit Labor’s negative gearing proposals by showing how they would “create market chaos” and be “difficult to police”.

The modelling was prepared by Brian Haratsis, MacroPlanDimasi’s executive chairman and a member of the Property Council of Australia, who is a friend of Greg Paramor, a former chairman of the Property Council. Paramor, who is a friend of Morrison, reportedly made the request to Haratis to produce the modelling after meeting with Morrison.