Ministers want to expand the scope of UK surveillance laws to give more public authorities – including a pensions watchdog and the Environment Agency – the power to access vast databases of personal phone and computer data.

Five additional public bodies are to be allowed to obtain communications data under the Investigatory Powers Act – frequently dubbed the snooper’s charter – as they are “increasingly unable to rely on local police forces to investigate crimes on their behalf”, according to documents published by the government.

The US whistleblower Edward Snowden once described the act as the “most extreme surveillance in the history of western democracy”.

The Civil Nuclear Constabulary, the armed police force in charge of protecting civil nuclear sites; the Environment Agency; the Insolvency Service; the UK National Authority for Counter Eavesdropping (UKNACE), an anti-espionage service and the Pensions Regulator are poised to benefit from strengthened powers.

The authorities join an established list that includes police forces, government departments and public agencies including the Health and Safety Executive.

A Home Office spokesperson said: “To protect national security and investigate serious crimes, law enforcement and relevant public authorities need the ability to acquire communications data.

“These powers are only used where it is absolutely necessary and proportionate and are independently authorised by the Office for Communications Data Authorisations, except in urgent or national security cases.”

The government has laid a statutory instrument to bring about the changes to the act – the first step of the parliamentary process – which will be debated by MPs and peers before it comes into force.

A memorandum published online explains the reasoning behind the proposed addition of each of the five bodies to the legislation.

The Environment Agency is responsible for investigating more than 400 different types of offence, which result in more than 40,000 suspected offences each year, including £600m of waste crime annually, the document says.

The former environment secretary, Michael Gove, has previously called for powers to access communications data for the agency.

The Insolvency Service, which investigates fraudulent trading committed by company directors and cases involving breaches of company director disqualification orders, wants to access data so it can analyse itemised billings, internet protocol addresses and underlying e-mail account details.

UKNACE, which detects hostile technical espionage and eavesdropping activity against UK assets in UK government buildings and embassies, needs the powers to identify and locate potential attackers or illegal transmitting devices, the memo states.

The Pensions Regulator has recorded a “dramatic” increase in enforcement activity since it became responsible for enforcement of employer automatic enrolment duties, the document says.

The Civil Nuclear Constabulary says it needs the powers to fully assess risk to nuclear sites in the UK, although the threat is determined to be low, the memo says.

The Investigatory Powers Act, which passed into law in 2016, requires web and phone companies to store everyone’s web browsing histories for 12 months and give the police, security services and official agencies access to the data, as well as providing provides authorities with powers to hack into computers and phones and to collect communications data in bulk.