The members of the Sarna community have set August 24 as the deadline for their demand to be met unless the attire is changed.
Talks between church representatives and the community failed over the issue.
The statue, which was unveiled by Cardinal Telesphore P Toppo in May, portrays Mother Mary in a red border sari and holding Jesus Christ in a way tribal women of Jharkhand hold their babies, by tying them to a white cloth.
The statue created trouble in the area with some seeing it as a tactic to convert tribals.
The church is located in an Oraon-majority area and is maintained by the Marianists, who look up to Mary as their model.
One of them came up with the idea for the statue and installed it. A source in the church said that the cardinal Toppo, who is also the Archbishop of Ranchi, came to know of it only the day he unveiled it.
The cardinal refused to comment on this but the source indicated he approved of the idea.
The Akhil Bharatiya Adivasi Mahasabha has taken umbrage at this portrayal.
"What they have shown Mother Mary to be wearing is the traditional dress of the Sarna people. We are demanding that the statue be restored to the traditional way of portraying Mary. We fear that this statue will later become a tool for conversion," said Sarna priest Bandhan Tigga.
Various Sarna organizations took out rallies in June. Earlier this month, the All Churches Committee met Sarna representatives in Ranchi. Sarna leaders said the committee had refused to take the statue down.
"They told us it was not an issue at all, and that the matter was being pushed forward by those with vested interests," said Jiten Oraon, general secretary of the adivasi mahasabha.
Churches committee secretary Manmasi Ekka of the Gossner Evangelical Luteran Church said deliberations are still going on.