You have some obligations under your employment contract to provide the organisation with data. In particular, you are required to report absences from work and may be required to provide information about disciplinary or other matters under the implied duty of good faith.
You may also have to provide the organisation with data in order to exercise your statutory rights, such as in relation to statutory leave entitlements. Failing to provide the data may mean that you are unable to exercise your statutory rights.
Certain information, such as contact details, your right to work in the country and payment details, have to be provided to enable the organisation to enter a contract of employment with you. If you do not provide other information, this will hinder the organisation’s ability to administer the rights and obligations arising as a result of the employment relationship efficiently.