The upper house of the Dutch parliament is to carry out its own investigation into potential conflicts of interest involving senators and the other jobs they do, Trouw reported on Wednesday

Earlier this week, investigative website Follow The Money reported that a VVD senator, Anne-Wil Duthler, had a company which was hired in 2013 by the public health ministry to advise on the draft text for new legislation on reforming the social work system.

After being approved by the lower house, the bill scraped through the senate by a majority of one (37-36). Duthler was one of the senators who voted in favour.

Party leaders in the senate have asked senate clerks to identify all the rules there are for ensuring that senators do not become embroiled in conflicts of interest, Trouw said.

The recent case has focused attention on the senate and ‘that impacts the entire institution,’ Tineke Strik, who leads GroenLinks in the senate. ‘We have to be able to explain what our rules are’.

Membership of the senate is not a full time job and senators are paid €29,000 a year for meeting each Tuesday in the month.

Senate chairwoman Ankie Broekers-Knol told broadcaster NOS that the other jobs which senators do add value to the work of the senate itself.