This is behind-the-scenes footage during the making of the National commercials.  There is no sound to the footage and its quality is rough (amateur) and very bright and over-exposed.

It shows ABBA getting ready for filming footage for the five National commercials: getting made-up; hair adjustments; waiting for the crew to be ready etc.

At the same time, ABBA recorded a couple of promos for "their new TV Special" (ABBA-dabba-dooo!! (or ABBA in the Beginning as it was known in Australia)) for Channel 9. One was voiced by Björn, and one by Frida. 

Out-takes for this, together with much better quality behind-the-scenes footage, were included in the fabulous video release Essential Stockholm.

Broadcast information
Ch7, Australia and some very brief footage shown in the 1994 Australian programme Re-Björn ABBA.
Other (better quality) footage was included in the video release Essential Stockholm.

 

Apparently there was a National Money, Money, Money clip which was made up of out-takes from the National commercials.

The fan who told me about this can only recall seeing it on the Saturday morning music programme Sound Unlimited on Channel 7 (Australia) and doesn't know who would have made it and said it was strange that Channel 7 had the clip because the Nine Network were more associated with the National campaign and ABBA at the time and National sponsored the ABBA from the Beginning special where the commercials were first shown.

It may be that National may have sponsored Sound Unlimited for a while based on this photograph. The National font looks the same. It was never, as far as we know, called ‘NATIONAL Sound Unlimited’ even though the banner below shows that. It would however explain why an ABBA clip featuring National products would be shown on 7’s programme.

National TV Commercials x5, 1976; 
Making the National Commercials, 1976

 

Thanks to Ian Cole and also to Rod Kirkman for info on the Money, Money, Money clip. Also thanks to Greg Martinez c/o ABBAtalk.
YouTube link c/o thepiperchile