The economic affairs minister took gas companies more seriously than government safety supervisors, according to evidence at the six-week enquiry into what has gone wrong in Groningen.

This week the enquiry restarted into how decades of gas extraction caused ever more earthquakes and damage for local people, and why compensation schemes have failed so badly. It will run until October 14.

Jan de Jong, former inspector general of mining at the SodM supervisor, criticised former minister Henk Kamp for failing to take its urgent advice to reduce gas extraction in 2013, reports NOS.

De Jong said that there was back door communication between the government and NAM, owned by Shell and ExxonMobil and responsible for mining. ‘I found it strange that behind our backs a letter was going to the minister,’ he said. ‘We had the idea that the NAM was taken more seriously than our advice.’

Bart van de Leemput, former NAM director, told the enquiry there was a ‘long list’ of things that they could have done better, reports NOS. But he pointed a finger at NAM shareholders Shell and ExxonMobil. They, alongside the state, were in charge of the scale of gas production.

Enquiry members, however, said it was a fact that the NAM had lobbied for more gas production.

The enquiry aims to find out who was responsible for incorrect decisions made, damage done, and money wasted in compensation efforts. The Dutch government has taken profit from the gas extraction since the 1960s and made more than €417 billion, according to the CBS.

On Thursday afternoon, former economic affairs minister from 2010 to 2012 Maxime Verhagen will be questioned.