Group work as a form of cooperative learning has been shown to promote learning in many aspects. However, challenges may arise for group work when members have different expectations and little to no familiarity with each other. This action research was to investigate how well the online peer assessment activities (in the form of Moodle workshops) implemented in two different undergraduate courses would promote individual contribution in a subsequent group project and enhance individual achievements. Online peer assessment activities were introduced in Cohort 2020-21 with the purpose to enhance team collaboration in academically heterogenous groups. The assessment scores of Cohort 2020-21 $(N = 70)$ were compared with those of the previous cohort $(N = 69),$ which had no peer assessment activities, using independent samples t-tests. Additionally, students’ opinions about the online peer assessments were identified from the qualitative comments of the teaching-and-learning evaluations of one course and the focus group discussion of another course. Findings showed that students who had participated in online peer assessment activities were perceived by their peers to have better collaboration in the group work than those who had not. However, no evidence suggested that better team collaboration would associate with higher achievements in the group project, nor would the implementation of online scaffolded peer-assessed activities directly connect to higher academic performance in the individual final assessment. How peer assessment activities could be adjusted using the functions of Moodle workshops to cater for the needs of students are discussed.