Plans to dredge the River Tay at Perth Harbour, described as a “game changer” for the port’s fortunes, could be postponed until 2020.
Perth and Kinross Council is still trying to strike an agreement with two global energy giants.
Shell and Ineos (formerly BP) complained to Marine Scotland about the project, arguing it could put ships at risk.
The companies say they have an agreement with Crown Estates to protect their pipelines, which prevents dredging work.
Councillors will be brought up to speed on negotiations next week.
A joint report by David Littlejohn, head of planning and development, and investment manager Serge Merone states that talks between the council and the firms have been “constructive” but more time is needed to reach a solution.
The report adds it will no longer be possible to begin work next year but a target date has been set for January-March 2020.