Tens of thousands of protesters have flooded back to Istanbul in a chorus of angry chants and a shower of red flares, challenging a demand from the prime minister to disperse.

The protesters in Takism Square are an eclectic mix of secularists, liberals, socialists, communists and anarchists, representing broad-based concern about police violence and disaffection with the ruling Justice and Development Party (AKP).

Fans from the city's three biggest soccer clubs also united to denounce the government, shouting that they stand "arm in arm against fascism".

"I have never experienced this friendship, this solidarity among Turks before," said Fenerbahce supporter Rustu Ozmen.

"We have to keep coming, we can't give up because Erdogan hasn't quit yet," the 29-year-old lawyer added.

Protesters set off red flares to loud cheers from the crowd that packed out the entire square.

The renewed demonstration comes after the prime minister Recep Tayyip Erdogan called for them to stop.

Most observers say the crowd is far too big take on, but AKP party spokesman Huseyin Celik said the situation was in hand.

"The process is under the control of the government, and is becoming normalised and increasingly in line with common sense," said Mr Celik.

He also dismissed any talk of calling early elections to resolve the crisis.

"You don't decide on early elections because people are marching on the streets," he said.

Mr Erdoagn, who has won overwhelming support at successive elections, said the government is running like clockwork.

Unrest enters second week

The unrest started last weekend after police cracked down heavily on a small environmental demonstration to save Gezi Park from demolition.

In the capital Ankara, hundreds of riot police used tear gas and water cannon to disperse some 5,000 demonstrators from the central Kizilay Square.

The police pursued the protesters who took refuge in side streets off the square, which is the nerve centre of the Turkish capital.

Several people were injured, according to local media reports.

Mr Erdogan has faced international condemnation for his handling of the protests.

The European Union has called for a "swift" probe into police violence in the clashes.

But Mr Erdogan hit back and said people in similar protests in other European countries would "face a harsher response".

The national doctors' union says the civil unrest has left two protesters and a policeman dead while almost 4,800 people have been injured across Turkey.

ABC/AFP