The breakaway group, which is headed by South African player Wayne Ferreira, is set for talks on the future of the sport with Grand Slam bosses this week after releasing the names of the 62 players who have voiced their support of the new union.
Top players such as Lleyton Hewitt, Marat Safin, Goran Ivanisevic and Yevgeny Kafelnikov are all on a list of 62 players, who are said to be members of IMTA.
However the union's position may have been weakened by a statement from ATP player representatives Todd Martin and Todd Woodbridge that casts doubt on the backing of the fledgling IMTA.
The ATP representatives stated: "IMTA's lawyers and leaders unfortunately are engaged in a campaign of self-promotion.
"No Top 100 singles players from major tennis countries such as France, Spain, Germany, England and all of South America are listed as involved with the group.
"Those who are on the list include a number of inactive players. We question what, if any, real commitment many players on the list have made to the IMTA.
"Since the release of the list, we have contacted a number of the players identified, and each of them has affirmed that they are not represented by IMTA for any purpose.
"The voice of players in dealing with the Grand Slams and other issues currently facing the game is the ATP player leadership elected by all ATP player members."
On releasing the list, ITMA spokesman Ferreira explained: "We felt the time was ripe to release the list of players supporting the IMTA.
"Given the quality and quantity of the players that have stepped forward to support the IMTA, we now feel that we have the critical mass necessary to move forward and to seek recognition from the governing bodies of tennis, including the ATP."
IMTA representatives are hoping to discuss topics such as scheduling, governance and financial issues affecting tennis when they meet Grand Slam officials.
"Everyone in tennis needs to understand that the players are the sport," said Henri-James Tieleman, the IMTA's administrative director.
"The players have been kept in the dark for too long about issues that impact them financially and even sometimes physically."
The row over the breakaway tennis union - the International Men's Tennis Association (IMTA) - has escalated after the ATP accused the group of being "engaged in a campaign of self-promotion".
