Ministers have been criticised for regarding travellers as “more worthy of preferential treatment” than military personnel in Northern Ireland.
The Democratic Unionist Party wants the law changed to ensure the “moral obligation” to provide care and support - outlined in the Armed Forces Covenant - is honoured in full in Northern Ireland.
Sammy Wilson, DUP MP for East Antrim, doubted Northern Ireland Office (NIO) figures which he said suggest 93% of the covenant is implemented in the country and questioned why this fell below the commitments met in England, Wales and Scotland.
He highlighted four differences in housing and health support offered to veterans, adding Northern Irish navy, army and air force personnel “risk all” rather than 93% when serving their country.
MPs heard wounded and sick veterans in Britain can receive priority NHS treatment for conditions caused during their service but this is not available in Northern Ireland.
Mr Wilson said this is because veterans are reluctant to declare previous armed forces service on security grounds and also due to restrictions in the Northern Ireland Act 1988.
He said priority for social housing for those leaving the services also exists elsewhere but not in Northern Ireland due to the law.
Up to three cycles of IVF treatment are offered to veterans in Scotland and England compared with one in Northern Ireland, Mr Wilson noted.
He added Northern Irish service personnel do not receive a council tax discount if their property is empty as they are living in a Ministry of Defence house.
This compares with a 50% discount offered to military personnel living elsewhere in the UK, the Commons was told.
Mr Wilson said circumstances and the law in Northern Ireland has resulted in these differences, telling MPs section 75 of the Northern Ireland Act requires key groups to receive protection.
He said: “It’s now interpreted as a legal barrier to the implementation of the covenant in Northern Ireland.”
Mr Wilson said a Government-commissioned review recommended the law is amended to give people leaving the forces and veterans the “recognition they deserve”.
Neither the MoD nor the Northern Ireland Office has acted on this, the MP said, as he noted: “(This is) despite the fact that section 75 was amended to include travellers.
“I must say it’s hard to understand why members of the travelling community should be regarded by the Northern Ireland Office as being more worthy of preferential treatment than members of the armed forces.
“That’s why I and my party have chosen through this Bill to highlight the inaction.”
Mr Wilson said he accepts his proposal “does not have universal acceptance” in Northern Ireland, noting Sinn Fein and the SDLP have opposed changes to ensure full implementation of the covenant.
He told the Commons: “Many find their attitude disappointing and disgraceful.
“Those signing up to join the armed forces do not exclusively come from the protestant and unionist community. The services recruit from all areas, faiths and political allegiances in Northern Ireland but both Sinn Fein and the SDLP seem happy to abandon them.”
Mr Wilson asked for his Armed Forces Covenant (Implementation) (United Kingdom) Bill, which has received cross-party support, to be given a second reading on January 29, 2016.
It is highly unlikely to become law without Government support and due to a lack of parliamentary time.