Michael Lohan -- Dina is Lying ... She Was WASTED

Michael Lohan is calling FULL B.S. on his ex-wife Dina Lohan ... claiming he's convinced she was drunk off her ass during her interview with Dr. Phil.

Michael actually participated in the Dr. Phil interview -- which was taped a few months ago -- and says it was obvious at the time, Dina was intoxicated ... and it was only 10 AM.

"I think when everyone sees the interview, they're gonna know she's not sober," Lohan tells us.

Michael says Dina needs to clean herself up ... if not for herself, for the sake of her children ... including Lindsay.

For her part, Dina claims she was totally sober during the interview ... and thinks the public should withhold judgement until the full interview airs on Monday.