EXCLUSIVE

Baltimore Ravens linebacker Ray Lewis is going for the block ... against his baby mama who's trying to hire a forensic investigator to comb through his finances -- all in an attempt to squeeze more child support out of him.

You'll recall ... Lewis and his baby mama Sharnika Kelly are in a nasty battle over child support for their young son -- and earlier this year Sharnika asked a judge to throw out their current agreement, claiming when she signed the deal back in 2001, Ray never disclosed his full income.

Sharnika even asked to have a forensic investigator come in and determine how much the NFL star is actually worth -- in hopes to have the current $3,500-a-month order increased.

Now Ray is putting his foot down -- and recently filed legal docs in Florida asking a judge to bar his baby mama from looking through his finances.

In docs, Ray argues the order established in 2001 is totally legit -- and says that Sharnika had a lawyer when she signed, so if she wanted to fight it ... she should have done so WAY back then.

A judge has yet to rule.