Diana Ross [ tickets ] unveiled details of her first tour with the Supremes in 30 years during press conference today in New York. Plans call for 30 concerts in all, but only 23 of the dates have been confirmed to date.

Tickets go on sale in at least five markets on April 10: Philadelphia, Detroit, Chicago, New York and Boston. Other on-sale dates for tickets are to be announced. Mountains of press have already surfaced about who will not be on the ''Return to Love'' tour: original Supreme Mary Wilson and Cindy Birdsong, the latter of whom replaced original member Florence Ballard.

''It's not a reunion tour,'' Ross said. ''I never considered it a reunion tour.''

Joining Ross will be Lynda Laurence, who replaced Birdsong in 1971 and was a Supreme until 1973, and Scherrie Payne, who was a Supreme from 1973 to 1977. Payne replaced Jean Terrell, who replaced Ross in 1970.

"Change is part of the Supremes,'' noted Ross. ''Lynda and Scherrie (sister of Freda Payne of ''Band of Gold'' fame) have been Supremes for 30 years. I invited all eight of the former Supremes to be part of the tour.''

Ross told the press conference Tuesday (4/4) at Vanderbilt Hall in Grand Central Station that she had been planning a solo tour until Arthur Fogel, of tour promoter TNA International, called with this offer.

Fogel tried to woo Wilson onto the tour as well, but the deal fell apart after a few weeks of negotiations. Wilson recently told Access Hollywood that she turned down $2 million because Ross was guaranteed $20 million. Other reports assert that Wilson recently turned down a sweetened offer of $3 million to join the tour, but Fogel told the packed press conference not to believe figures that the media has thrown around. Ross will be performing the Supremes' chestnuts in their entirety for the first time since she left the group in 1970 to launch a solo career. Ross has performed Supremes' songs only as part of medleys since 1970. Laurence and Payne are expected to sing lead on some songs as well.

A section of the show will be devoted to Ross' solo career because she believes it is what her fans want.

After the press conference, Fogel told liveDaily that there will be no opening act and that arenas were chosen over amphitheaters because ''Supremes fans don't want to sit on the lawn.''

Over the course of the tour, funds will be raised to benefit three charities: the Elizabeth Glaser Pediatric AIDS Foundation, City of Hope and A Better Chance.

There will be no European tour. ''This may be once in a lifetime opportunity to see this,'' said Ross, adding that there are no plans for future tours.