FRANKFURT (Reuters) - Volkswagen's luxury cars unit Audi on Monday cancelled some production shifts at its headquarters in Ingolstadt, southern Germany, amid the first signs of an economic impact of flooding in the region.

The early and the late shifts assembling the A3 and Q2 vehicle models in Ingolstadt were cancelled, the company said in an alert to staff on Sunday, made available to Reuters on Monday.

"This is in response to the intensifying flooding situation in the region," the statement said, adding that the factory was currently not directly affected by flooding.

Navigation authorities earlier on Monday warned that parts of the river Rhine in southern Germany, an important shipping route for commodities and fuels, were closed to cargo shipping after heavy rains raised water levels.

The high water levels leave vessels insufficient overhead space to sail under bridges, and prevents vessels sailing to Switzerland.

(Reporting by Christina Amann; Writing by Ludwig Burger; editing by Matthias Williams)