Boro fans are being urged to follow safety signs as they make their way to home games at the Riverside Stadium.
Diversions are currently in place during the development of the £10 million Middlehaven Dock Bridge.
The new road crossing is due to open next summer, paving the way for work to start on the proposed snow centre.
Before the Queens Park Rangers match earlier this month thousands of supporters ignored the warning and diversion signs and chose to walk through two-way traffic even though there were no available footpaths.
Following consultation with Cleveland & Durham Road Policing Unit it was established that there was no possibility of a guaranteed safe route for pedestrians across the Shepherdson Way/The Halyard junction.
Temporary road gates have been installed close to the Hudson Quay office complex to prevent pedestrian access before home matches and restrict vehicle movement.
This operation proved successful before the Norwich City match last Tuesday and will be repeated for all MFC home games this season.
Unfortunately many supporters still ignored the directional signs, instead scrambling up a grass bank and then either scaling a safety barrier onto Shepherdson Way or walking through part of the building site.
A Middlesbrough Council spokesman said: “The creation of the Dock Bridge is a major civil engineering project which will enhance not just Middlehaven but the town as a whole and the wider Tees area.
“During such works the safety of football fans, other pedestrians and motorists is of paramount importance, and the diversions are there for a reason.
“The actions of those seeking shortcuts are at best foolhardy and at worst dangerous.
“We therefore strongly advise all supporters to follow the yellow and black directional signs.
“We will continue to endeavour to keep any disruption to a minimum, and thank fans for their patience and understanding.”
Additional high level fencing will be installed ahead of the Brentford game on Saturday, September 30 to prevent this practice happening again.
The yellow and black signs direct supporters to The Leeway, passing under Shepherdson Way, so accessing the Riverside Stadium via Car Park A.
Routes are unaffected after the final whistle as all roads and car parks are closed until pedestrians have left the area.
The new road and lifting bridge - with associated lighting, drainage and landscaping works - will feature a 95-tonne steel bridge deck with 120 tonnes of steel reinforcement and 159 tonnes of pre-cast concrete units.
The new highways will link Shepherdson Way with Scott’s Road, crossing a narrow channel connecting Middlehaven Dock to the River Tees.