Too many governments are "rubber-stamping" mass surveillance programs, the UN human rights watchdog warns, according to BBC News.

In a report, the UN body said more needed to be done to ensure that surveillance was balanced against its harm to personal privacy. It added that mass retention of data to aid surveillance was "neither necessary nor proportionate".

The document was written by the office of Navi Pillay, the UN High Commissioner for Human Rights, who said it revealed a "disturbing" lack of transparency about the reasons governments approve or start large-scale monitoring of what people do online.

Mass surveillance, Pillay said, was becoming a "dangerous habit rather than an exceptional measure" for governments.

These programs necessarily interfered with privacy, and governments must do more to ensure that this curbing of freedoms was "neither arbitrary nor unlawful".

The further that governments went in scooping up information about citizens, the harder they needed to work to justify the snooping and monitor it to guard against excess, said Pillay.

The report said laws that set out how surveillance could be carried out must be publicly available and demonstrate specific reasons why the monitoring was taking place.

It said measures to force net companies, mobile operators and others to retain data on what people did online and whom they talked to had little justification.

Simply gathering data, even if it was never consulted, could potentially curb privacy because too few states put good limits on who could look at the data and what it could be used for.

"The constant stream of new revelations shows how disturbingly little we really know about the precise nature of surveillance," said Pillay.