Henry McLeish, who was in the post between 2000 and 2001, told BBC’s Good Morning Scotland that he believes using only proportional representation (PR) would mean parties would have to co-operate.
He said the first past the post element should be removed.
Mr McLeish told the broadcaster: “You could have a PR system that could retain the constituencies, but possibly have two members, but elected on a different basis .
“What that would do is give you a parliament that would never have an overall majority. That would be one box that I would gratefully tick.
“Secondly, it would mean that people would have to speak to each other.”
Mr McLeish led a Labour-Lib Dem executive in the parliament’s first session.