The National Tax Service (NTS) announced a series of reform measures on Thursday to prevent corruption and irregularities by its officials.

Under the measures, high-ranking tax officials will be banned from dining out or playing golf with executives or tax advisers of the nation’s top 100 business groups and their holding companies.

The tax service will set up a team to investigate corruption cases involving high-ranking public servants. Tax officials will also be required to sign a written pledge on work ethics when assigned to a different position or promoted.

The tax service plans to launch a committee led by a civilian chairman to oversee and supervise tax inspections in order to gain public trust of those inspections.

The tax agency will also re-evaluate results of all tax audits on large companies that post 500 billion won in sales. Under the measure, tax inspections on about 100 to 200 large companies a year will be re-evaluated.

It is the second time this year the NTS announced reform measures since April.