The fire-damaged M1 motorway may not fully reopen until late next week, Transport Minister Mike Penning has said, causing further traffic chaos for motorists.
While two lanes should be open later, motorists should avoid the route where possible because congestion will be likely, Mr Penning told Sky News.
A blaze at a scrapyard under an elevated section of the motorway on Friday morning caused significant damage to the bridge's structure and forced the closure of junctions one to four.
Drivers trying to get away for an Easter holiday and football fans attending the FA cup semi-finals at Wembley faced nightmare disruption.
The full three lanes of each carriage-way may not reopen until "the middle to the end of next week", Mr Penning said, because parts of the structure remained unsafe.
"The bridge has been damaged by the fire quite badly and that means we have to make sure it's safe for the motorist and safe for our workers underneath the bridge," he said.
"This is a pre-cast concrete bridge and the heat has damaged it so badly there are steels exposed that are part of the structure of the bridge."
He said the hard shoulder had been particularly badly damaged by the fire and engineers are working to erect a structure under the bridge to give it the stability necessary to carry the weight of traffic.
Advising motorists to use alternative routes, he said: "I'm very conscious that if people think the motorway is open on Monday and we only have a couple of lanes, we will have congestion.
"So what I'm saying to them is, only use the M1 if you have to."
Earlier, he told BBC News: "It is going to be a frustrating time (for motorists) but the key is their safety. It's not safe at the moment and that's why it's not open."
He said police were investigating what was stored at the scrapyard and how the incident took place.