The Senate unanimously passed a bill Thursday intended to encourage more participation in elections by enrolling voters when they interact with the Registry of Motor Vehicles or MassHealth unless they opt out.

The bill (H 4671) passed 38-0 while Secretary of State William Galvin, a supporter of the measure who is facing a primary challenge, made an appearance in the Senate.

Senate Majority Leader Cynthia Creem said the bill would also move Massachusetts into a multistate organization that helps officials weed out improper voter registration.

The House previously passed the bill 130-20. The Senate adopted one amendment, which was sponsored by Sen. Karen Spilka.

Calling it a "great bill," Sen. Anne Gobi said there were 680,000 people in Massachusetts who have not registered to vote but who are eligible to register.

Pam Wilmot of Common Cause told the News Service the House and Senate bills are very similar but the Senate bill contains changes recommended by the governor's office. She said she was working to have the House agree to those changes, which could clear a path for the bill to advance to Baker's desk without the need for a conference committee.