Despite Romania having recently joined the EU, the nation has been denied full rights to freedom of labour movement.
With 12 goals from 28 international appearances, Niculae's case looks strong, but he has failed to appear in 75 per cent of his country's games in the last two years.
Caley argue that Niculae, with a rich career CV at Dinamo Bucharest, Sporting Lisbon, Standard Liege and Mainz in the Bundesliga, is deserving of special dispensation.
Highlands and Islands Labour MSP David Stewart, a former Westminster parliamentary colleague of Home Secretary Jacqui Smith, will speak on Caley's behalf in their appeal hearing.
Stewart, a keen Caley Thistle supporter and club trustee, confirmed to The Scotsman: "I have been approached by the club regarding the situation Marius now finds himself in. When Marius signed for the club, like many fans, I was thrilled - he is a player of stature, experience and talent.
"This is the club's most significant signing yet and shows the clear ambition of Inverness Caley Thistle to progress further up the SPL.
"I have looked at the Home Office conditions which have to be met for the granting of a work permit for a footballer in Marius's circumstances.
"One is that the player's home country must be within the top 70 of FIFA's world rankings. Romania's national team position meets this requirement.
"Another condition is that the player must have played for his country in at least 75 per cent of its competitive full international matches during the two years preceding the application.
"Despite his international record as a player Marius, unfortunately, does not meet this requirement. However, these are only guidelines for an initial application and I'm aware there have been many precedents of even internationally unknown, non-EU players with no links to the UK being granted work permits.
"The application by Marius will now go to appeal and the important thing now is to gather support for the legal team to use at the hearing.
"With this in mind I have today launched an e-petition.
"I have also written to Jacqui Smith, a former Westminster colleague and current Home Secretary, calling on her to intervene to support Marius's case."