Britain on Tuesday criticised police tactics against pro-democracy protesters in Hong Kong, warning that the use of live rounds could heighten long-running tensions.

"Whilst there is no excuse for violence, the use of live ammunition is disproportionate, and only risks inflaming the situation," Foreign Secretary Dominic Raab said in a statement.

Raab said the shooting again showed the need for "constructive dialogue" between both sides.

"We need to see restraint and a de-escalation from both protesters and the Hong Kong authorities," he added.

This came after the European Union called for "de-escalation and restraint".

"In light of the continuing unrest and violence in Hong Kong, the European Union continues to stress that dialogue, de-escalation and restraint are the only way forward," EU spokeswoman Maja Kocijancic told reporters.

"While initial positive steps to engage members of the public and various sectors of society in dialogue have been taken, further efforts are needed to restore trust," Kocijancic said.

"More than three months since the protests began, the right to assembly and the right to protest peacefully must continue to be upheld in line with the [Hong Kong] basic law and international commitments." (AFP)