Algeria's ruling FLN party showed more signs of turning its back on Abdelaziz Bouteflika as new protests against him began on Friday, with one senior party figure saying in an interview overnight the long-serving president was "history now".

Bouteflika has reversed a decision to stand for another term after mass protests against his rule, but stopped short of stepping down and says he will stay on until a new constitution is adopted. He has been losing allies in recent days since returning from medical treatment in Switzerland.

The remarks by Hocine Kheldoun to Ennahar television late on Thursday were another major setback Bouteflika, who hoped to pacify Algerians by promising to take steps to change the political landscape dominated by a ruling elite for decades.

Kheldoun, a former spokesman for the ruling party, became one of the most senior FLN officials to break with Bouteflika publicly, saying the party had to look forwards and support the aims of demonstrators protesting against Bouteflika.

On Friday, thousands of protesters gathered in central Algiers to keep pressing Bouteflika to step down. Unlike past Fridays, when demonstrations usually peak in the early evening, this time crowds began forming earlier.

"FLN go," some shouted amid a heavy police presence across the capital.

"Those who think we are tired are wrong. Our protests will not stop," said doctor Madjid Benzida, 37.

Some parents had brought children: "I want a better future," said Mohamed Kemime, 10, draped in a national flag.

Tens of thousands of Algerians have staged peaceful protests for weeks, demanding a new era with younger leaders who would offer greater social freedoms and prosperity.

Bouteflika, 82, has been in office for 20 years but has rarely been seen in public since suffering a stroke in 2013. Protesters say he is no longer in a fit state to rule.

"GAME OVER"

A former minister who is familiar with Bouteflika's inner circle told Reuters that the president could not survive given the pressure building against him.

“Game over. Bouteflika has no choice but to quit now," the former minister said on condition of anonymity.

Algeria is a major oil and gas producer, but so far exports have not suffered from the unrest. Its biggest oil field Hassi Messaoud and its Hassi Rmel gas field have not been affected, a source from state oil giant Sonatrach told Reuters.

Many Algerians say that the ailing president and other veterans of the 1954-1962 war of independence against France should hand over power to young technocrats who can focus on unemployment, poor services and stamping out corruption.

The military, which has traditionally played a behind-the-scenes power broker role, has distanced itself from Bouteflika and stayed in its barracks throughout the crisis. It is expected to retain influence under all scenarios.

Algeria was relatively untouched when the 2011 "Arab Spring" uprisings swept away veteran autocrats in the Arab world. Bouteflika and his allies, effective manipulators of the opposition, managed to avoid major unrest by spending oil money on the population, handing out low interest loans and housing.

Bouteflika was credited with ending a civil war against Islamist insurgents in which tens of thousands of people were killed in the 1990s, and many Algerians long accepted heavy-handed rule as the price of stability.

But the public has lost patience with deteriorating economic conditions and the ruling party's failure to make the transition to a new generation despite the president's failing health.