VICTORIA'S human rights watchdog has launched an election-year assault on the Brumby government's so-called war on knife crime.

As Labor prepares to fight a ''tough on crime'' campaign, Human Rights Commissioner Helen Szoke has condemned the government for breaching its own Charter of Human Rights with legislation that would empower police to randomly search unaccompanied children for weapons.

Dr Szoke told The Age the bill - now before Parliament and expected to be passed within weeks - gave police excessive powers and was an unreasonable incursion on individual rights.

She has written to Police Chief Commissioner Simon Overland seeking a briefing on how police propose to use the extended powers, hailed by Premier John Brumby as the toughest in Australia.

Her stance pits the commission against not only the government but the opposition and Victoria Police, who all support boosting police search-and-seize powers in response to community concern about rising levels of street violence.