Figures show that the police – who have seen a drop in officer numbers of 20,000 – are reducing the amount of tests being carried out.
Analysis of Home Office data shows there has been a fall of 37 per cent in England and Wales.
There were 270,000 fewer tests carried out in 2016 compared with six years earlier.
Nine police forces have seen a fall in testing of 60 per cent including the City of London, Manchester, Humberside and Gwent.
Labour blamed government cuts for the reduction.
Shadow Policing Minister Louise Haigh said: “Across the country, forces are faced with growing demand and shrinking resources and it is areas like road policing that suffer.
“Make no mistake, if the police do not have the time to clamp down on drink driving, lives will be put at risk.”
Jayne Willetts, of the Police Federation, said there are around 3,600 specialist roads policing officers targeting poor driving behaviour, but added: “They are often used to respond to calls from help from the public.
“Due to the austerity cuts there are simply not enough officers to attend domestic violence, burglary, public order incidents.”
But a Home Office spokesman said: “Police have the powers they need to keep our roads safe and latest figures show that deaths as a result of drink driving on British roads are at a record low.
“It is for chief constables and locally elected police and crime commissioners to decide how to deploy their resources.”
“The provisional funding settlement for next year will increase funding by up to £450million across the police system, including an increase of up to £270million in funding going directly to police forces to spend on local priorities.”