Some companies in Britain are using voice recognition computer software to detect if their employees are lying when they ring up saying they are sick and need a sick day.

Companies say this has stopped around $1 million in false claims but employees say this is no way to treat them as it breeds distrust in the workplace.

In New Zealand the employment laws around sick days clearly state that sick leave can be used by the employee when they or their spouse or dependent is sick or injured.

An employee must let their employer know as soon as possible about their intention to take sick leave - preferably before starting work but otherwise as early as possible after becoming sick.

If the employer suspects the employee is faking their illness they can ask for proof in the form of a medical certificate for the worker or their dependent within three days.

It is also the employers right to request proof after three days of sick leave. This includes for a Monday if the employee has taken Friday off sick.

If the employee does not provide proof when requested without reasonable excuse, the employer has the right to withhold the payment for the sick leave period until it is provided.

For most employees there is a minimumn entitlement of five days a year sick leave after six months of employment and five days for each 12 month period.

If someone is in a job for less than six months, sick leave can often be taken in advance and deducted from the entitlement when it comes up.

For part time workers the sick leave is calculated as "relevant daily pay", which means the hours that the employee would normally work are what they get paid for sick leave. For example if an employee works a five hour shift they would be paid five hours sick pay.

If the hours vary over the week but there is a minimum of 10 hours worked in a week, the total sick pay will be averaged out for the preceding four week period. To calculate relevant daily pay, see the calculator here

Sick leave can be accumulated to a maximum of 20 days but cannot be cashed in on or paid out when the job ends.