BackgroundEarly intervention following occupational injury can improve health outcomes and reduce the duration and cost of workers’ compensation claims. Financial early reporting incentives (ERIs) for employers may shorten the time between injury and access to compensation benefits and services. We examined ERI effect on time spent in the claim lodgement process in two Australian states: South Australia (SA), which introduced them in January 2009, and Tasmania (TAS), which introduced them in July 2010.MethodsUsing administrative records of 1.47 million claims lodged between July 2006 and June 2012, we conducted an interrupted time series study of ERI impact on monthly median days in the claim lodgement process. Time periods included claim reporting, insurer decision, and total time. The 18-month gap in implementation between the states allowed for a multiple baseline design. In SA, we analysed periods within claim reporting: worker and employer reporting times (similar data were not available in TAS). To account for external threats to validity, we examined impact in reference to a comparator of other Australian workers’ compensation jurisdictions.ResultsTotal time in the process did not immediately change, though trend significantly decreased in both jurisdictions (SA: −0.36 days per month, 95% CI −0.63 to −0.09; TAS: 0.35, −0.50 to −0.20). Claim reporting time also decreased in both (SA: −1.6 days, −2.4 to −0.8; TAS: -5.4, −7.4 to −3.3). In TAS, there was a significant increase in insurer decision time (4.6, 3.9 to 5.4) and a similar but non-significant pattern in SA. In SA, worker reporting time significantly decreased (−4.7, −5.8 to −3.5), but employer reporting time did not (−0.3, −0.8 to 0.2).ConclusionsThe results suggest that ERIs reduced claim lodgement time and, in the long-term, reduced total time in the claim lodgement process. However, only worker reporting time significantly decreased in SA, indicating that ERIs may not have shortened the process through the intended target of employer reporting time. Lack of similar data in Tasmania limited our ability to determine whether this was a result of ERIs or another component of the legislative changes. Further, increases in insurer decision time highlight possible unintended negative effects.Electronic supplementary materialThe online version of this article (10.1186/s12889-017-4998-9) contains supplementary material, which is available to authorized users.