Stress is a complex response that begins when people are exposed to various stressors, including psychological and environmental factors, which are associated with negative cognitive effects. However, little is known about their interactions within the brain. This research aimed to examine the influence of low and high noise levels in the workplace on changes in brain activity in the prefrontal cortex (PFC) during stressful psychological tasks by measuring synchronized functional near-infrared spectroscopy (fNIRS) and electroencephalogram (EEG). The results showed a decreased oxygenated haemoglobin (HbO) concentrations in the right dorsolateral PFC and part of the frontopolar area when exposed to higher noise levels compared to lower levels. Results also showed a higher correlation between fNIRS-HbO and EEG-alpha power under stress conditions compared to other EEG bands. We suggest that higher levels of noise in the workplace may be directly related to increased psychological stress. © Published under licence by IOP Publishing Ltd.