The South Stand was built in 1938
Headingley Carnegie Stadium will have its capacity cut to 20,500 for the next two years.
Leeds Rugby have agreed with building control authorities to reduce its capacity from 8,000 to 6,000, following safety tests on the South Stand.
Repair work on the stand will start immediately at a cost of £250,000.
The club hopes it will be reopened in time for Leeds Rhinos' traditional Boxing Day clash with Wakefield Trinity Wildcats.
Capacity in the famous terrace was halved for the Rhinos' final home game of the season in September and it was completely shut for Carnegie's encounter with Coventry on 19 October while testing was carried out.
Our next challenge is to deliver a permanent long term plan
The building work means the stand will be closed for at least Carnegie's next five National League One games.
Chief Executive Gary Hetherington said: "I am relieved a solution has been found and, although it is a costly one that deals with the short term, we can now start work immediately.
"Our next challenge is to deliver a permanent long term plan.
"The restricted areas will be at the edges of the stand and therefore will only marginally impact on the South Stand supporters over the next two years.
"We will be asking supporters to comment on any new designs once they are complete."
The South Stand was renovated in 2000, at a cost of £750,000.