On Monday, after winning their Nations League game 2-1, Danish players complained about the hole that had appeared in the centre circle. They said it was at least 30cm deep.
“I don’t know what’s going on with this amateur stadium,” midfielder Pierre-Emile Hojbjerg told the press.
The OFB has warned that if there is a danger of further holes appearing, Friday’s sold-out game against France in Vienna could be called off.
“The field is being examined with X-rays with a special device to see if other cavities can appear,” an OFB spokeswoman told AFP.
“The analysis should be completed on Wednesday evening” when, she said, a meeting was scheduled between stadium officials and European governing body UEFA.
“It is likely that there was a significant increase in the level of groundwater from the nearby Danube, caused by heavy rains on Sunday night to Monday,” she said.
“The waters exerted upward pressure on the pitch, which caused the formation of a cavity, leading to a hole.”
The OFB said it had 1,000 square meters of turf available “in the event that the top layer of grass must be changed quickly” if new holes are detected.
It said it had used a roller to compress the soil.
On Tuesday, OFB president Bernhard Neuhold told local media that he could not “say that there is no further danger”.
“There can always be scenarios that could lead to a cancellation of the match,” he added.
Monday’s game was beset with problems.
Kick-off was delayed 90 minutes by a power cut.
“The outage affected neighbouring districts of Vienna and was caused by faulty power lines. The technicians say that the heavy rains on Sunday caused this problem,” the OFB told AFP.
More rain is forecast in Vienna on Thursday and Friday.