After-hours incentive funding for general practice was introduced in 1998 through the introduction of the Practice Incentives Program (PIP). In 2010, a national audit of the PIP identified after-hours incentive funding as having the greatest levels of non-compliance across 12 PIP components. The audit specified the need for secondary data sources to ensure practice compliance. In this article, we examine the drivers of the 1998-2013 PIP mechanism to inform development of a fair, transparent and auditable after-hours incentive funding scheme for Tasmania. The PIP after-hours incentive funding mechanism paid, at diminishing levels, for anticipated burden of care (practice size), claimed method of providing care (stream) and remoteness of practice. Increasing remoteness rather than practice size or stream is the primary determinant of urgent after-hours attendances per practice in Tasmania; after-hours attendances to residential aged care facilities are unrelated to individual practice location or stream but concentrated in urban areas. The PIP after-hours incentive funding mechanism does not preferentially support practices that provide after-hours care and arguably led to perverse incentives. A new after-hours incentive funding mechanism embodying pre-specified objectives - such as support for (unavoidable) burden and/or provision of care to residential aged care facilities - is required. Claimed provision is considered an inappropriate funding determinant.