Facebook has been caught on the back foot again over its data privacy practices, following an investigation by the New York Times.

The newspaper has disclosed fresh details about ways the social network shared access to users' data with other tech firms, including Amazon, Apple, Microsoft, Netflix, Spotify and Yandex.

In some cases, the other companies have said they were not even aware they had special access.

Facebook has defended its behaviour.

It said it never gave others access to personal data without people's permission and had seen no evidence that the data had been misused.

However, it has acknowledged again that it should have prevented third parties being able to tap into users' data, after publicly announcing that it had ended the privilege for security reasons.

Examples given by the NYT include allowing others' products the ability to read users' private messages and to see the names, contact details and activities of their friends.

Facebook's handling of the matter has drawn criticism, including tweets from its own former chief security officer Alex Stamos, who has called on it to disclose more details about what special access it provided to whom.

The latest revelations follow a series of scandals including the Cambridge Analytica data harvest, incitement to violence in Myanmar, also known as Burma, evidence of Russian and Iranian meddling in the US elections, and several data-exposing bugs.

These have undermined public confidence in Facebook, led to calls for new regulations and prompted demands for a leadership rethink.

"We have to seriously challenge the claim by Facebook that they are not selling user data," commented Damian Collins MP, chair of the UK Parliament's Digital, Culture, Media and Sport Committee.

"They may not be letting people take it away by the bucket load, but they do reward companies with access to data that others are denied, if they place a high value on the business they do together. This is just another form of selling."

The Irish Data Protection Commission, which takes the lead on Facebook in the EU, has issued a brief statement: "We are aware of the media reporting from earlier today. We are currently assessing what next steps, if any, are required."