German manufacturers' order backlog is at a record high, according to a survey released on Monday, as companies struggle against supply bottlenecks in meeting high demand.

Even without a single new order, production could continue for 4.5 months, the Munich-based ifo institute said in a statement, citing the results of a survey in which around 2,000 companies took part between April 7 and 22.

In the previous survey, in January, the figure had been 4.4 months, while the long-term average for an order backlog was 2.9 months, the institute said. The data is seasonally adjusted.

"This recent increase in backlog is only slight, which indicates that the intake of new orders is gradually decreasing," Timo Wollmershauser, head of forecasts at ifo, said, adding that German manufacturing would "really take off" if the supply-chain issues were to ease in coming months.

(Reporting by Rachel More; Editing by Bradley Perrett)