The Australian white ibis (Threskiornis molucca) is considered to be an urban pest along the east coast of Australia. The non-specific diet and broad habitat requirements of ibis have facilitated their successful exploitation of the urban environment. Ibis are considered a pest because they pose a threat to aircraft safety, scavenge food at waste-management sites, cafés and parks, and compete with other native species for food and habitat. This study assesses a new ibis-management technique, the application of ‘egg-oil’ to suppress hatching. On other species, egg-oiling has been shown to be environmentally safe and socially preferable to culling adult birds. Approximately 5 mL of food-grade canola oil was sprayed upon each egg, and both incubator and field trials were used to investigate the efficacy of this technique on ibis and to determine the optimal application time and frequency of egg-oil. Treatment eggs were given an application of oil during the 23-day incubation period either once per week, or once early (<7 days), mid (~14 days) or late (>18 days) incubation. All four treatments were observed to be 100% effective at preventing ibis eggs from hatching during the laboratory trial and more than 98% effective during the field trial. These results indicate that applying canola oil to ibis eggs once, at any time, during the 23-day incubation period is sufficient to prevent ibis eggs from hatching. The field trial also showed that 30% of ibis, across the four oiling treatments, continued to incubate the unviable eggs for up to 54 days longer than the normal incubation period. Given that ibis are multibrooded, raising up to three successful clutches in a breeding season, the increased time devoted to incubating oil-treated eggs could reduce the opportunity for multiple broods, compared with conventional egg destruction. The egg-oil technique offers an additional tool for land managers to conduct ibis reproduction control, which should reduce the amount of time required to conduct ibis management, consequently reducing the cost to land managers.