By Alan Baldwin

LONDON, April 19 (Reuters) - The FIA has praised Formula One drivers for their "valuable" contributions ahead of a teams' meeting on Monday where proposals to amend the rules to improve the quality of racing will be put forward.

The sport has seen its biggest change in decades in the car's structure and engine, with new power units split roughly 50 percent for electric power and 50 percent for combustion power.

However, drivers complained about the impact on racing and expressed safety concerns because they had to ease off the accelerator early and adopt a free-riding style without acceleration in high-speed corners so that the combustion engine could recharge the battery.

FIA President Mohammed Ben Sulayem said via social media on Sunday that there were "constructive and collaborative discussions" between the FIA and the drivers ahead of a meeting with team managers and Formula 1 stakeholders.

He added, "The drivers made valuable contributions regarding the modifications they believe should be made, particularly in the areas of vehicle energy management to ensure safe, fair, and competitive racing."

Ben Sulayem said that a series of meetings had been held with representatives of the teams' technical departments and engine manufacturers to discuss the proposed changes.

He added, "Safety and the interests of all parties involved in the sport are the main focus of these discussions."

He continued, "After tomorrow's meeting, the final proposals for electronic voting will be presented to the FIA World Motor Sport Council."

Mercedes driver George Russell, who is also the head of the Grand Prix Drivers' Association, told reporters last week that the relationship between the drivers and the FIA is "probably the closest" it has been in years, and that the sport's governing body knows what needs to be done.

He said, "There have been some very positive discussions with the FIA, and everyone agrees on what we are trying to achieve."

He added, "I think the two main points are to conduct the qualifying trials at maximum speed, that is, not lifting your foot off the accelerator pedal and not following a free driving style without acceleration, and then reducing the speeds at which the race is finished."