Planning for South Africa's next national census, which will for the first time see population information collected electronically, will kick off this year, members of parliament were told on Wednesday.

Presenting the Statistics South Africa budget vote in Parliament, the Minister of Planning, Monitoring and Evaluation Nkosazana Dlamini-Zuma said the 2021 population count is vital to plan for South Africa's needs.

"Conducting a population census is the biggest statistical survey any country and national statistics agency can undertake," she said.

She said the data would be collected via computer assisted personal interviews.

This will improve the quality of data collected and reduce the time-lag between data collection and the dissemination of results.

The 2011 census put the South African population at 51.7-million people, up 6.9-million from 2001.