The two groups called on Kowit to account for the promotion of an officer suspected of ignoring brutality and criticised him for delays in solving the disappearance of Muslim lawyer Somchai Neelaphaijit.

The groups are the Academic Network for Democracy (AND) and the Chulalongkorn Network for Ethics (CNE).

"Kowit cannot escape responsibility for undermining the police," CNE leader Anan Laolertworakul said.

Anan said Kowit had no justification for promoting Colonel Rithirong Thepchanda from superintendent of Pathumwan police station to deputy commander of the Metropolitan Police Bureau.

Rithirong is being investigated for his handling of rival crowds supporting and opposing ousted prime minister Thaksin Shinawatra at Central World in August, he said.

A fight broke out and Rithirong was accused of taking no action to restrain the violence of the pro-Thaksin demonstrators.

Under Kowit's command, many police officers had been named as suspects in the Somchai case, Anan added, noting that the investigation had made no headway.

Rebutting criticism on crowd control, Colonel Pallop Pathummuan, incumbent Pathumwan police chief, said his officers had no clear legal guidelines with which to handle rival crowds.

"No cases relating to street protests have ever reached the Supreme Court to set a precedent," he said.

Pallop denied the police turned a blind eye to violence at Central World.

Ten police reports have recommended rival protesters be prosecuted for violence and Rithirong is under investigation by the National Counter Corruption Commission for alleged abuses, he added.