Lebanon's interior minister has asked security forces to show restraint at a planned mass protest against the government this weekend, but says there is concern groups of violent trouble-makers might infiltrate the crowd.

Nohad Machnouk said Friday that troops won't allow anyone to damage property or break into government buildings. He says he is committed to keeping protesters safe at Saturday's rally.

Two rallies last weekend brought 20,000 people into the streets of Beirut, driven by anger over garbage piling up in the streets. The government's failure to resolve the trash crisis threatens to turn into a wider protest against a political class that has dominated Lebanon since the end of the civil war in 1990 and is widely seen as dysfunctional.

Dozens were hurt in the clashes last weekend.