Working part time does not reduce the salary requirement pro rata. However, an exemption has been made for parental leave and maternity leave.
Article 8.2a. Implementation wage criterion 30% rule
In the event that the salary referred to in Article 10eb, first and second paragraph, of the Decree , of an employee as a result of taking parental leave or maternity leave in an annual period is lower than the amount referred to in Article 10eb, first paragraph, respectively second paragraph, of the Decree, in the wage period in the application of that article in respect of the employee, the wages referred to in that article, which the employee would have enjoyed if he had not taken parental leave or maternity leave.
Maternity leave / parental leave does not affect your rights to keep the 30% ruling, even if your salary is below the salary threshold. When applying for maternity leave and/or parental leave, you will keep the benefit of the 30% ruling based on your salary applicable on your working hours mentioned in your employment contract.