Renault has warned the Formula 1 teams it supplies engines to that they anticipate further problems at this weekend's Malaysian Grand Prix.
The French manufacturer provides power units to several constructors, including current champions Red Bull, and those teams have struggled for performance throughout winter testing.
However, Renault's head of track operations, Remi Taffin, suggested that the humidity at the Sepang circuit will prove to be one of toughest tests on the 2014 calendar in terms of reliability.
He told reporters: "Sepang is one of the circuits whose technical requirements will change under the new regulations.
"In the V8 era the circuit sat towards the middle of the table for the challenge it posed for engines but now it will be one of the toughest races of the year."
Only three Renault-powered cars finished the Australian Grand Prix earlier this month, with four-time world champion Sebastian Vettel being the highest-profile retiree.
