If the number contains a single ‘0’ at the beginning – then it is localised.
So if the numbers contain 00 at the start or just the international code – it will recognise it correctly.
You may have to re-format the cells as in some cases the cell can be in a 'text' format and would need to be changed firstly to a 'number' format and then to a 'custom' format where you can add the area code so that this is displayed for all numbers before importing.
Please click here to view more information on this issue and how to re-format into a number format.