The peak body for internet users in Australia has formally requested that a review of the attorney general’s data retention scheme be brought forward, calling the legislation a “monumental stuff-up” as the government seeks to expand access to include civil lawsuits.

Laurie Patton, the chief executive of Internet Australia (IA), has written to the parliamentary joint committee on intelligence and security to request that the review of the Data Retention Act be held sooner owing to “continuing disquiet” over its effectiveness and implementation.

The legislation was passed in 2015 with the stated aim of combating terrorism. The committee is due to review the data retention scheme in late 2018.

Patton said the review of the law was more urgent given the request from the Attorney General’s Department for submissions on a proposal to expand the scheme to grant access to litigants in civil lawsuits, which could include divorce cases or even copyright infringement.

As the law now stands, only specified security and intelligence agencies can request metadata collected under the scheme. The joint committee recommended in its report on the legislation that civil litigants be prohibited from being able to access the data.

But the AGD said in its consultation paper there was “the risk that restricting parties to civil proceedings’ access to such data could adversely impact the effective operation of the civil justice system”.

It appealed to “stakeholders with an interest in the civil justice system and privacy” to make submissions on the issue in mid-December and it will receive them until 27 January.

Patton told Guardian Australia that the review needed to be brought forward because of the call for submissions and the encroaching deadline for industry compliance.

“What we’re saying is let’s not wait another year – firstly because it’s a debacle in its own right and secondly, if the government or the AGD has this idea of expanding it to include civil litigation, then that really should go back to the PJCIS.”

IA gave evidence to the committee’s original inquiry into the law in late 2014, arguing that the proposed legislation was “fundamentally flawed” and drafted by lawyers who did not fully understand the internet.

“Our fears have already been proven prescient,” wrote Patton in his letter addressed to Michael Sukkar, the Liberal party MP and committee chair, on Tuesday. The committee and the AGD have been contacted for comment.

Under the act, specified telecommunications providers, primarily internet service providers, are required to have systems in place by April 2017 to retain all their customers’ metadata for two years.

But even then, Patton and IA believe it will be unlikely to achieve its purported purposes.

Discrepancies in how those providers are meeting their obligations, as well as questions over how compliance will be monitored, means the scheme is arguably “of dubious benefit for its stated purpose of combating terrorism”, according to Patton.

IA believes there to be more ISPs in Australia than the 180 that were granted funding from the AGD to help meet their costs of compliance, and that there are therefore hundreds of providers not known to the department and who will not be collecting and storing data as required to under the law.

“If we must have data retention, then surely we should aim to have legislation that will work?”

Patton reiterated IA’s concerns to Sukkar that the costs of the scheme will be passed on to consumers, with PricewaterhouseCoopers’ estimate of the $738m cost of compliance to the industry over 10 years thought to be based on incomplete data.

Security agencies had sought a data retention scheme for more than a decade but successive attorney generals had resisted, he said.

“This exercise has become a monumental stuff-up. Not only is it causing confusion amongst ISPs, it has clearly failed to deliver what the law enforcement agencies had sought for so long.”

A spokesman for the AGD told Guardian Australia that its 2015-16 annual report on the use of telecommunications interception and access was still being prepared.