The Premier League has been urged to stop making "excuses" by the Equality and Human Rights Commission after publishing its interim report on disability access at clubs' grounds.
Top-flight clubs were criticised last month by the Culture, Media and Sport select committee, which said some clubs were expected to miss an August deadline to become compliant with disability access requirements.
In response, the League released a statement on Wednesday alongside its interim report and said more work needed to be done, but that clubs "deserved credit" for improvements already completed.
The League said that some clubs faced "significant challenges" in meeting the deadline due to the "differing ages and nature of stadia".
But Equality and Human Rights Commission chairman David Isaac said clubs faced legal action if they failed to show how they are making disabled access easier.
"Disabled fans give their money to their club just like everyone else," Isaac said.
"They buy the shirts and loyally support their teams. Premier League promised that disabled access would be improved by the start of next season so it is disappointing that a number of clubs will fail to meet that deadline. The time for excuses is over.
"Clubs need to urgently demonstrate to us what they are doing to ensure they are compliant with the law and how they are making it easier for disabled fans to attend matches. If they don't they will face legal action."
According to a report released by the Culture, Media and Sport select committee on January 16, Premier League clubs could face heavy fines and even points deductions if they fail to meet the August deadline.
The report stated that four clubs - Chelsea, Liverpool, Crystal Palace and Bournemouth - were likely to miss the deadline, and also criticised West Ham for reducing provision for disabled supporters since it took over the Olympic Stadium.
It accused some clubs of "prioritising finance over improving access", although West Ham said the report was based on out-of-date information.
The committee stated it will support the Equality and Human Rights Commission in taking legal action against individual clubs and their respective governing bodies in the event of evidence of their "systemic" non-compliance.
The Premier League said in response on Wednesday that clubs had unanimously agreed in September 2015 to improve their disabled access provisions.
"Premier League clubs have embarked on a substantial programme of work and rapid progress has been made," read a statement.
"The improvements undertaken are unprecedented in scope, scale and timing by any group of sports grounds or other entertainment venues in the UK.
"The interim report submitted to EHRC, DWP (Department for Work and Pensions) and DCMS (Department for Culture, Media and Sport) provides an update on the work done up to December 2016, and details the considerable improvements that have been delivered.
"What is clear from the interim report is that clubs are committed to building on the long tradition of disabled fans being welcome at football grounds while recognising that there was, and is, more work to be done.
"Given the differing ages and nature of stadia, some clubs have, and continue to face, significant built environment challenges.
"For those clubs cost is not a determining factor. They are working through issues relating to planning, how to deal with new stadium development plans, how to best manage fan disruption or, in cases where clubs don't own their own grounds, dealing with third parties.
"Clubs deserve credit for committing to and delivering the extensive work detailed in this interim report.
"What is also clear is that even more progress will be achieved in creating the appropriate levels of access for disabled football fans, as envisaged by the ASG and EHRC, by our own deadline of August 2017.
"Beyond that date clubs will continue to engage with their disabled fans and enhance their provisions in the coming months, years and beyond."
While Premier League clubs have been criticised, lower level clubs were praised for their approach towards compliance with regulations set out in the Accessible Stadia Guide.
Derby, Tranmere, Wrexham and Egham Town were named as "exemplars of best practice" in terms of providing access for disabled supporters.
James Taylor, head of policy and public affairs at disability charity Scope, said disabled football supporters were still being discriminated against.
"Today's interim report highlights how much more clubs need to be doing for their disabled fans," Taylor said.
"We know It can be incredibly difficult for disabled fans to watch Premier League football live. As the Culture, Media and Sport committee recently warned, too many football grounds still lack suitable accessible facilities and stands.
"Too often, public attitudes, inaccessible venues and facilities and a lack of information mean disabled people are unable to enjoy sport like everyone else does.
"When it comes to watching football live all disabled fans just want a level playing field."