'Basketball Wives' to VH1 -- Pay Up Or We Walk

The "Basketball Wives" are drawing a clear line in the sand for the network execs -- either up their salaries or they'll walk ... this according to sources connected with the show.

We're told filming began last week for the 5th season ... but Shaunie O'Neal, Evelyn Lozada, Tami Roman and Suzie Ketcham do NOT have locked contracts.

According to our sources, the "Wives" are in the process of renegotiating their contracts and they all want major pay raises, claiming the show does quite well for the network.

Our sources say VH1 is refusing to pony up more cash. We're told before filming started, execs made it clear that salary increases would not happen and if any cast member had a problem with that ... they could be replaced.

Despite the deadlock, we're told production schedules were sent out and the girls began filming in hopes a deal would be worked out shortly. So far, a deal has not been reached and neither side is budging ... so we're told the "Wives" are planning to walk out next week if VH1 can't agree to the terms.