However, both the options are now displayed for users if they manually enter ‘EU’ in the search bar.
A spokesman of the company rejected allegations that it was influencing "the tone of political debate" on its platform.
Facebook’s spokesman said: "People who search for ‘EU’ when they are using our status tool will see a full range of options enabling them to add if they are thinking of leaving or remaining in the EU.
"People scrolling through the list of activities see options based on what their friends and other people have been using."
The two official campaigns on the referendum- Vote Leave and Britain Stronger in Europe-are also not featured in the list for users.
The social network said that it did not include the campaigns as they were not under the "non-profit organisation" category.
The referendum, which is scheduled to be held on 23 June, will decide whether the UK should remain in or leave the European Union.
This article is from the CBROnline archive: some formatting and images may not be present.
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