The group accuses the Guru Nanak Sikh Gurdwara in Blakenhall of leaving people in wheelchairs outside the main prayer room and making them sit behind screens in the dining room because they are unable to observe the custom of sitting on the floor.
Papers have been filed with the County Court in Birmingham and letters have been sent by Paul Uppal and Pat McFadden, both seeking re-election as MPs in Wolverhampton, reminding the Gurdwara of its obligations under disability discrimination laws. Around 10,000 people regularly use the Gurdawara in Sedgley Street.
The campaigners say people in wheelchairs cannot get up to the prayer room, the Darbar Sahib, because a lift is not always available. Those with mobility problems say they have to sit on benches outside the main room.
The committee says no-one is being excluded and that plans are in place for a new building that will improve access to the prayer room.
In the dining area there is a blue screen between the open plan floor, where worshippers sit for food, and an area with tables and chairs.
And in the prayer room on either side of the entrance are wooden screens with windows in, which the campaigners say will segregate people who sit on chairs at the back of the room.
Rajinder Bassi, chairman of the Sikh Forum Wolverhampton, said around £5,000 has been raised through donations to fund the legal challenge.
He said: "What is happening to disabled and older people is degrading. They are missing out on the spiritual aspect and want to be able to join others upstairs. There's nothing in our faith that says the temple should do this."
Dee Kaur, aged 63, of Yew Tree Lane, Tettenhall, has been in a wheelchair since 1996 and has brittle bones as well as a condition caused by problems with her antibodies. She said: "I want to go upstairs but can't.
"The tables here are kept out of sight. We are being excluded."
Malkit Singh, aged 38, of Massbrook Grove, Fallings Park, has cerebral palsy.
He said: "I have to sit downstairs. It's like I'm being hidden away."
The forum's vice chairman Iqbal Kaur added: "This has been going on for three years. It goes against their human rights."
The management of the Gurdwara says more facilities for disabled worshippers will be provided under plans for a £2 million revamp.
In a statement a spokesman, who did not wish to give his name, said: "The services are provided in line with Sikh traditions where all are welcome to visit and pray at the Gurdwara Sahib. We make as far as possibly practical reasonable adjustments that are also consistent with our practices to accommodate people with disabilities taking account of our faith's traditions.
"The Gurdwara is governed by direction from Akaal Takhat Sahib Jee - the Sikh Supreme Authority and this is written within the Gurdwara constitution registered with the Charities Commission since its establishment in 1969.
"In line with the Sikh principles of worship and serving the community through its open door policy for all regardless of gender, age, race, wealth or faith including those of no faith, the Guru Nanak Sikh Gurdwara Management Committee have over the years provided a series of 'reasonable adjustments' which cater for those who are unable to be seated in the two main areas of the Gurdwara, these being the Darbar Sahib where the religious programmes are held and the Langar Hall where the congregation are served blessed food and also socialise with family and friends.
"These provisions will be modernised once the approved new building costing nearly two million pounds is constructed this year."
In a letter sent last year and published on the forum's website, Conservative Mr Uppal said: "Since seating was removed in 2012 I understand that these members of the congregation have found it increasingly difficult to sit on the floor in the Darbar Sahib to listen and partake in prayers.
"It is incumbent upon me to remind the management committee that in many of the congregation's views, this is perceived as discrimination and is understandably causing considerable concern to congregation members, as well as not complying with national legislation."
Labour's Mr McFadden also wrote: "I understand of course that in the Gurdwara people sit on the floor. All are equal and sit in the same way before the Guru Granth Sahib. This issue which has been raised with me is what provision should be made for worshippers who, by reason of disability or frailty, cannot sit on the floor. I understand that some Gurdwaras provide some seating to cater for such provision. It is not my role to make a religious judgement. I have, at my constituents' request, checked the position with regard to the legislation which covers access for disabled people and its applicability to places of religious worship."