The union wants stricter punishment for assault on police officers and simplifying rules on the use of firearms.
The union held a press conference following yesterday's murder of officer Ranko Grkovic.
"How many of us have to be killed before bad and sloppy laws are changed," SPH leader Dubravko Jagic asked.
He pointed the finger at Justice Minister Vesna Skare-Ozbolt, saying she refused the union's request to increase punishment for those who kill or assault police officers. He added Prime Minister Ivo Sanader and Interior Minister Marijan Mlinaric were equally guilty because they had done nothing to improve the position of police.
The SPH is also disgruntled because its initiative to amend the law on breaches of public peace and order was rejected, and asks that police be provided with protective equipment and appropriate weapons.