Khaled Drareni is the founder of the Casbah Tribune website and a correspondent for French-language channel TV5 Monde and press freedom group Reporters Without Borders (RSF).
He was arrested on March 7 while covering an anti-government protest and was accused of "inciting an unarmed gathering and damaging national integrity".
He was later released then re-arrested.
Prisoners' support group CNLD said Wednesday an Algiers court had "upheld the rejection of a request for the provisional release" of Drareni.
Weekly anti-government protests known as "Hirak" rocked the North African country for over a year and only came to a halt due to the novel coronavirus outbreak.
Last month, authorities blocked three news websites that had covered the protests.
Amnesty has called Drareni's prosecution "outrageous" and accused the government of "arbitrary prosecutions aimed at silencing... activists and journalists" linked to the Hirak protest movement.
It said last month that authorities were endangering detainees' health "given the risks of a COVID-19 outbreak in prisons and places of detention".
Algeria ranks 146 out of 180 countries on RSF's world press freedom index for 2020.