There are currently 1.5 million people addicted to prescription drugs in the UK. The abuse of these types of substances is taking place in the shadows and its extent is still unquantified.
Local GPs need to report their suspicions and collate information to illuminate this problem.
Lack of action would lead to "catastrophic consequences", Mr Vaz said.
The committee cited work by the All Party Parliamentary Group for Involuntary Tranquilliser Addiction which estimates that 1.5 million people are addicted to these type of drugs, far higher than those who are in treatment for addiction to illegal drugs.
Today is a "big opportunity" for two officers involved in the plebgate row to set the record straight, according to the chairman of the home affairs select committee Keith Vaz.
Detective Sergeant Stuart Hinton and Sergeant Chris Jones will appear before the committee for the second time in as many weeks, after the committee found their evidence to be "misleading".
Mr Vaz told BBC Breakfast: "I'm sorry to say that in a number of respects they have given evidence that was not strictly accurate, so this is their big opportunity today to come before the committee and to explain why that happened and to correct the record."
The chairman admitted he was frustrated with the time and cost of the inquiry: "I think we're getting near the end but I share your frustration and that of the viewers that this has taken so long and cost so much money - almost a third of a million pounds - and involved so many police officers."
The MP concluded that it was in the best interests of the taxpayer, Andrew Mitchell and the police officers involved that the saga be brought to a close.
A total of 19 clients of rogue private eyes will be investigated for illegal activity, the data watchdog has confirmed.
In a letter to Keith Vaz MP, Information Commissioner Christopher Graham said 125 victims were believed to be affected by the companies and individuals under criminal investigation for data protection breaches.
MPs had threatened to release a full list of 102 of those involved if action was not taken.
A list of clients of rogue private detectives will not be published by MPs "for the time being" after the data watchdog intervened.
Information Commissioner Christopher Graham urged the Home Affairs Select Committee not to publish a list of 102 organisations and individuals who used rogue investigators while his office conducted its own investigation.
Committee chairman Keith Vaz MP said: "The Information Commissioner has given the committee an explicit commitment that he will pursue this matter to its appropriate end and that the victims will receive justice."
Vaz said Graham would appear before the Committee after his "scoping exercise" so that MPs could assess whether the investigation "fulfils all that is required".
The Home Affairs Select Committee will publish a list of 102 clients of rogue private investigators on Monday if the Serious Organised Crime Agency (Soca) does not do so first, chairman Keith Vaz has said.
Keith Vaz, chair of the Home Affairs Select Committee, has said the actions of Cabinet Secretary Sir Jeremy Heywood over material held by The Guardian was "unprecedented" and called for a full statement from David Cameron to explain the government's involvement in the incident:
Home Affairs Select Committee chairman Keith Vaz has written to the Met Police's Assistant Commissioner Cressida Dick to ask if the force has any further interest in the companies on a list of names linked to rogue private investigators.
He has asked Ms Dick, as well as the Information Commissioner's Office, to confirm when the public will be able to see those names, whose identities are currently being protect at the behest of the Serious Organised Crime Agency (Soca.)
The list, which was created by Soca, was passed to the Home Affairs Select Committee on strict confidentiality grounds - prompting Mr Vaz to demand an explanation as to why it should be kept secret.
It breaks down firms that featured in evidence in prosecutions of Operation Millipede, the Soca investigation that led to the conviction of private detectives for fraud, as well as firms that were relevant to the inquiry but not used in evidence.
Chairman Keith Vaz said the Home Affairs Select Committee "remains concerned" after it was handed a list of 102 names of companies and individuals linked to rogue private investigators.
The Committee remains concerned that it holds a list that Soca [Serious Organised Crime Agency] has classified as secret, even though it is evidence given as part of our inquiry.
This is an important step forward in establishing the facts.
Mr Vaz also confirmed there are five organisations or individuals on the list who are being investigated as part of Operation Tuleta, Scotland Yard's investigation into allegations of computer hacking.
Home Affairs committee chairman Keith Vaz said it is "worrying" that Police and Crime Commissioners "seem able to side-step the statutory process for dismissing a chief constable".
Mr Vaz said: "Police and Crime Panels should make more active use of their powers to scrutinise decisions such as this.
"We will be returning to this area when we carry out our next major inquiry into Polic eand Crime Commissioners, towards the end of this year."