Delivery is typically three weeks after build, but some dealers are reporting spare capacity which means Volkswagen can accept more orders from the network.
Volkswagen head of fleet Vince Kinner said: 'Leasing companies typically do not buy cars through a huge number of suppliers. Because they are not using all our network some retailers have spare capacity.
'Leasing companies need to broaden their supplier base by two or three dealers. Small and medium-sized leasing companies are happy to widen their supplier base but we are getting a mixed reaction from the larger leasing companies. Some are willing to build in new suppliers but others prefer to remain with their traditional suppliers.'
Fleets are currently waiting up to 12 weeks for vehicles to be delivered, although Volkswagen will increase production of right-hand drive Golf and Passat from January.
A Passat diesel saloon ordered today will not be built until the end of November and a Passat estate will not be built until the New Year.
Kinner added: 'We are asking leasing companies not just to tender on price because that is identical through the dealer network because of national agreements, but to tender on quality of service. By switching dealers and using more dealers, end users and fleet managers will get their cars quicker.
'It is worrying that we have got people waiting for cars for 12 weeks when we have a similar car within our stock which is freely available.'