St Barbara (ASX:SBM) said the final investment decision for its Simberi Expansion Project in Papua New Guinea will be delayed to between the late second quarter and the early third quarter of fiscal 2026 due to unresolved amended tax assessments, according to a Wednesday filing with the Australian bourse.

The company said funding arrangements have not progressed significantly due to the tax matter, but has continued early works at the project, including the procurement of a ball mill, design of the new grinding circuit, and expansion of the camp facilities.

The company's shares were up almost 1% in recent Wednesday trade.