The European Union says the Nauru Government must meet its international human rights obligations.
Five of the seven opposition MPs in the Nauru Parliament have been expelled for more than a year, officially for speaking to foreign media about the government's actions.
Three of those MPs are now facing criminal charges in relation to a protest outside the Parliament earlier this month.
There has been widespread criticism of the situation on Nauru, including from the New Zealand Government and the head of the Inter-Parliamentary Union, Martin Chungong.
Now the EU Delegation in the Pacific says the recent restrictions to freedom of expression, access to the internet and social media, as well as the arrests of the MPs, are disturbing developments.
It is calling on the Nauru Government to abide by its international human rights obligations and to uphold freedom of information and freedom of speech.