The Nationals have backed a call to limit mobility scooters to 6km/h.

Nationals Senator John Williams has secured support at the party's federal conference to push for new speed limits that he argues will reduce risk of accidents.

Senator Williams wants the speed limit to be dropped from the current 10kph, close to a light jogging pace, down to walking pace.

His campaign was prompted by the serious injury of his wife in a footpath collision with a scooter.

The motion backed at the Nationals conference includes a maximum tare weight of 150 kilograms for the scooters.

Senator Williams argued that because the drivers do not need a licence, insurance or medical checks to get behind the wheel, the lower speed limit would reduce the risk of accidents.

Successful motions from the Nationals conference inform future party policy.

Senator Williams is known for having significant influence in other policy areas in the past.