CZ Employment Start/End Notification (ONZ)

The oznámení o nástupu do zaměstnání / skončení for the ČSSZ in the ONZ 2022 XML structure — superseded by the JMHZ employee register since 1 April 2026.

Version	19.0.1.0.4
Edition	Community and Enterprise
Licence	AGPL-3
Requires	`l10n_cssk_payroll_declaration_base`

What it is for

The oznámení o nástupu do zaměstnání (ONZ, the form that also served as the odhláška) told the ČSSZ that an employee had started or ended an employment that is subject to sickness insurance.

This module builds a batch ONZ for a list of employees — either all starts or all ends — and exports it as XML, checked against the official ONZ2022_20230616.xsd. The data come from the employee and contract records, not from payslips. It belongs to the family of payroll filings built on l10n_cssk_payroll_declaration_base — see the Czech payroll guide.

The form can no longer be filed. See the next section.

Legal background

Since 1 April 2026 the employer meets the duty to notify the ČSSZ of the day an employee starts and the day the employment ends by registering the employee in, and removing them from, the evidence zaměstnanců under the JMHZ Act — § 94 of the Sickness Insurance Act as amended by Act No. 360/2025 Sb. (Art. XXIV, in force from 1 April 2026 under Art. XXXIV letter d).
No ONZ for older events either. Where the event happened before 1 April 2026 and the employer had not yet notified it, the duty is met in the new way (Art. XXV point 4 of Act No. 360/2025 Sb.). An employee registered on 31 March 2026 counts as registered in the new evidence (point 6).

The module therefore refuses to generate an ONZ on or after 1 April 2026, and one for an event dated on or after that day; notifications generated before then stay on their records. It does not produce the JMHZ registration.

Setting it up

On the company:

Value	Used as
ČSSZ variable symbol (VS), 8 to 10 digits	`<comp vs>`
OSSZ code, a number from 100 to 999	`dep`, the competent social security office. Defaults to 100.
Company ID (IČO)	`<comp id>`

The ČSSZ variable symbol (VS) and OSSZ code fields are not shown on any form; fill them in by importing them on the companies list. They are shared with the PVPOJ and ELDP modules.

Per employee: the birth number in Identification No, the date of birth (Birthday), optionally the place of birth, the private address, and the contract's Contract Start Date (for a start) or Contract End Date (for an end).

Preparing a notification

Payroll Declarations → CZ ONZ (registration), then New.

Choose the Event Type — Start of employment or End of employment. It applies to every employee in the notification.
Add the Employees.
Click Generate. The XML is built and validated against the schema. Mark Submitted and Reset to Draft work as on the other filings.

Generation stops without employees, without a valid VS or OSSZ code, for an employee without a date of birth, without the contract date the event needs, and — with a message pointing to the JMHZ registration — on or after 1 April 2026 or for an event dated from that day.

What each record contains

Item	Taken from
action (`act`)	1 start or 2 end
date filled in (`dat`)	the day you click Generate
birth number	Identification No, if it has 9 or 10 digits; otherwise left out
surname (`sur`), first name (`fir`)	the employee's name: the last word is the surname, everything before it the first name(s); separate first and last name fields (OCA `hr_employee_firstname`) are used when present
birth surname	the current surname
address	the private address; a trailing number in the street is the house number
start / end of the employment (`fro`, `to`)	the current contract's start and end dates
kind of activity (`rel`)	always 1
place of work (`per`)	the company's country

Limitations

Superseded since 1 April 2026 — see Legal background.
The birth surname is the current surname, and a surname of more than one word is recognised only with separate first and last name fields.
Only the two actions start and end; changes and corrections are not modelled. The kind of activity is always 1, also for agreements and small-scale employment.
The dates come from the contract current today, so a back-dated or replaced contract can give a different date than the one really notified.
Schema validation checks the shape of the file, not the content.