Members of the National Union of Journalists and the broadcasting union Bectu took the action after being told more than 160 staff at the Scottish Media Group face wage cuts or freezes.
Scotland's main ITV news bulletins - Scotland Today and Grampian Tonight - were drastically shortened and presented by stand-ins.
The action comes as SMG has revealed record profits and prepares to bid for the new ITV operating franchises. SMG won the Scottish franchise with a token bid, but it is now preparing a more realistic offer as other companies eye the market.
