THE 7km-long $57 million upgrade to Cunninghams Gap that took two years to complete apparently didn't stretch far enough with metres of mud, rock and rubble falling on either side of the recently completed roadworks.

Access through Warwick's gateway to Brisbane has been cut since late Sunday afternoon and it could stay that way until the end of the week.

A Transport and Main Roads spokesman said the landslides were caused by weather associated with ex-tropical cyclone Oswald.

"There are landslips towards the top of Cunninghams Gap, in the area where the shipping containers are located," he said.

"Road crews are working hard to clear the landslip material at the Gap and remove debris from the road near Aratula.

"It is expected that the highway will be re-opened to motorists later this week.

"The department is working hard to keep road users informed of any changes to the road network."

Cunninghams Gap was not the only road affected by the major flooding and heavy rain.

The O.O. Madsen Bridge was closed on Monday afternoon and reopened at 1pm yesterday afternoon, providing hundreds of stranded travellers access to Toowoomba.

A council spokeswoman said the Gap alternative via the Boonah back road was closed.

"We have received advice that there are trees down on the section east of Carrs Lookout," the spokeswoman said.

"Over the grid at the Teviot Falls in Scenic Rim Region there are landslips which will mean this road may be out for quite some time."

The department is working hard to keep road users informed of any changes to the road network.

Motorists are strongly encouraged to check the 131 940 website and phone line before setting out on their journeys.