A Renault booth during the 84th Geneva International Motor Show on Sunday Photo: CFP

Renault and alliance partner Nissan unveiled plans on Monday to integrate key operations and pursue economies of scale to keep up with big rivals like Volkswagen.

The creation of a new alliance management team was among the steps announced by Renault-Nissan boss Carlos Ghosn after 15 years of softly-softly cooperation between the French and Japanese carmakers.

Squeezed by the rising costs of emissions regulation at home and tougher competition in emerging markets, where demand is slowing, Western carmakers have looked to mergers, alliances and ad-hoc production deals to share costs and boost profitability.

Renault and 43.4 percent-owned affiliate Nissan are rolling out new models on a jointly developed mass-market vehicle architecture and in January raised their savings goal to at least 4.3 billion euros ($6 billion) by 2016.

Confirming moves that were flagged at the time, Ghosn named new executive vice presidents on Monday to run converged manufacturing, research and development, purchasing and human resource functions across the alliance, starting on April 1.

The Renault-Nissan CEO pledged an "immediate increase in efficiency," noting in an alliance statement that the savings would help to "deliver higher-value vehicles to customers and stay at the leading edge of innovation."

Renault and Nissan, which in turn owns 15 percent of Renault, lag behind Volkswagen, Hyundai-Kia and Toyota on platform scale - the number of vehicles assembled from a common architecture.

In the face of bolder rival tie-ups such as the Fiat Chrysler merger, Ghosn has argued that cultural sensitivities prevented faster Renault-Nissan integration.

As a result, analysts and insiders say, the alliance has missed significant savings opportunities over the years as Nissan and Renault went their separate ways on programs such as electric cars.