Many participants of Dutch pension funds receive a lower pension than they are entitled to, because their employers pay insufficient contributions, a collective of investigative journalists has suggested.

In a joint publication, daily De Groene Amsterdammer, television news programme Nieuwsuur and non-profit investigative platform Investico, concluded that companies often don’t register their workers with a sector scheme, or pay too low premiums.

As the problem usually surfaces much later, proving such low pension payments is difficult for duped employees, the researchers found after interviewing dozens of people in the sector.

They estimated that the issue could affect up to hundreds of thousands of participants and hundreds of millions of contributions, and concluded that participants’ confidence in a correct calculation of their pensions rights wasn’t justified.

In a clarification, co-author Gert-Jan Dennekamp of Nieuwsuur said the estimate was based on interviews with IT providers and specialists.

He added that published incidents, such as pensioners missing out on labour disability benefits at the €459bn civil service scheme ABP, and too low paid premiums at courier firm DHL, had been included as well as internal data of two sector schemes that could indicate a significant problem.

The investigators suggested that there had been several “incidents” at the €607m pension fund for the wood-processing industry (Houtverwerkende Industrie), that could have caused the scheme to miss out on “millions of contributions”.

However, the pension fund told Dutch pensions publication Pensioen Pro that things were “more nuanced”, and that it would come up with a more detailed response.

The researchers further claimed that 300 companies hadn’t registered their workers with the €3.1bn scheme for the meat-processing industry (VLEP), despite having registered staff at the Chamber of Commerce (KvK).

John Klijn, VLEP’s chair, said he didn’t recognise these figures, “as we annually discover approximately five employers who hadn’t registered their staff”.

He argued that the KvK’s figures “were often not up to date and that there were often good reasons for these differences”, but added that the discrepancies could justify an investigation.

Investico, which said it had approached 43 pension funds, also concluded that checks were inadequate.

It said that of the eight schemes that had responded, only the €86bn metal pension fund PMT made clear that it actively checked whether employers paid in sufficient contributions.

The platform added that data of employee insurance agency UWV had shown that no more than half of the sector schemes was able to compare their data with the UWV’s details through a link of their respective administrations.

The investigative collective cited an employee of the former pensions provider Syntrus Achmea who said that pension funds “were not willing to pay for stricter checks”.