Trust is a complex and context-dependent construct that is very important in collaboration theory. However, insufficient research into developing and building trust is continually emphasised in relevant studies. Therefore, this study aims to determine what the factors and dimensions of trust are within public safety networks (PSNs) and how to build collaborative trust within them. A questionnaire survey was conducted amongst 83 PSNs experts. The results were assessed using the partial least squares structural equation modelling method. Consequently, trust factors in PSNs were identified, grouped into dimensions, and a model for building trust was developed. Based on the assumption that trust positively affects the effectiveness of joint activities, the correlations between the identified dimensions were examined, and their impact on the process of building trust in PSNs was determined. The results indicate that building trust, within networks, is based on individual organisations' competencies and credibility. These features assist in developing transparent rules and determine the scope of relationships. This creates mutual cognition and focuses on collaborativeness, and consequently leads to the collaborative nature of trust.