Alterations to the proposed new road's layout combined with "construction inflation" would add an extra £7m to the £27m price of building the route.
Associated sports facilities to be created could cost up to £9.5m.
A meeting of the full council will next week be asked to approve the road's layout and sanction the start of the process acquiring the land needed.
Highland Council believes the new road is needed to ease travel across the city.
Officers have told councillors in the report: "The project will help mitigate the impact of climate change by reducing traffic congestion, improving journey times and support active travel through cycling and walking and thereby reduce the carbon footprint for traffic in and around the city of Inverness."
Alternations were made to the project designs following public consultation.
The planned new sports hub will be bigger and four sports pitches will be created at a different location than originally planned.
There will be a new golf practice area and land made available for the expansion of Kilvean Cemetery.
The alterations also include dropping a plan to make an area of land available for mixed-use development.
Council officers suggest in order to speed land acquisition, a compulsory purchase order will be published.
"All of the landowners affected by the project have been contacted and have been advised of the revised design development proposals," the officers said.
Earlier this month, the council said new proposals should not affect the planned 2015 construction start date.