Mercedes have had to postpone the planned introduction of an upgraded engine for the works and customer teams at this weekend's Canadian Grand Prix.

One of the most power-hungry circuits on the calendar, Montreal is the usual race of choice for suppliers to bring their first updates and particularly this year where it marks the one-third distance in a season where all key components are limited to just three for the year.

Renault, Honda and Ferrari are all expected to bring fresh and more powerful units, something that could put the German manufacturer at a rare disadvantage as their engines will have lost peak performance and be towards the end of their reliability cycle.

“Although we had hoped to introduce PU2 this weekend, a quality issue means that this has now been delayed by one race,” said a team spokesperson.

“All Mercedes-powered cars will be running PU1 for this weekend.”

Just to highlight the types of gains the other suppliers could make, rumours suggest Ferrari, despite ongoing tests into their ERS system, could have another 10 horsepower while Honda may have close to 30 additional horses in the back of the Toro Rosso.

“The updates are mainly to the ICE (internal combustion engine), focusing on improving performance," Toyoharu Tanabe, technical director at the Japanese manufacturer noted.

 A saving grace for Mercedes is the second unit should be ready for the returning French Grand Prix at Paul Ricard on June 24.