The Pyrites Creek bridges, at Anthony's Cutting near Bacchus Marsh, will close while structural supports and surfaces are fixed up from "late March", with early works beginning February 13.

The Melbourne-bound bridge will close for about 10 weeks, followed by the Ballarat-bound bridge, and another two weeks of "completion works".

"During each bridge closure, traffic will share the existing lanes of the open bridge, with two lanes maintained for westbound traffic and one lane open for eastbound traffic. A 40km/h speed limit will apply to all traffic through work zone," a department release states.

"All other traffic heading towards Melbourne will have the option to stay on the freeway or detour via the Old Western Highway. All over-sized and over-mass vehicles more than 2.55 metres wide will use the Old Western Highway detour."

There will be reduced speed limits on the freeway, and regular drivers are urged to consider taking the V/Line train to avoid up to 25 minutes of traffic delays.

"This proactive maintenance will consist of works on the structural supports and road surfaces of the eastbound and westbound bridges, ensuring the strength of the bridges for many years to come," the release states.

"The Western Freeway is a key freight route and an important connection for commuters between Melbourne and Ballarat, and this stretch of the freeway is used by around 20,000 vehicles every day."

There is still no word on the realignment of the Western Freeway at Pykes Creek, which was announced in 2020.

The federal government's infrastructure website, last updated February 3, 2023, notes "(t)his project is expected to commence construction in mid 2023 and be completed in mid 2024."