Over the last few years, Massachusetts has expanded access to the ballot box — but some top officials say the state still has not gone far enough.

Secretary of the Commonwealth William Galvin and Attorney General Maura Healey, both Democrats, testified Thursday before the Joint Committee on Election Laws in favor of allowing same-day voter registration.

“This proposal reflects my view that I think same-day is the final step we need to take to make sure voters have every opportunity to participate in every election,” Galvin said.

Healey called the right to vote “the heart of our democracy.” “We need to do all we can to reduce barriers to participation in our elections and ensure the ballot is fully accessible to all eligible voters,” she said.

Massachusetts has already been expanding access to the polls. Massachusetts voters had early voting for the first time in 2016. Beginning in 2020, residents will be automatically registered to vote when they make transactions at the state's Registry of Motor Vehicles or with MassHealth.

But Massachusetts still requires voters to register 20 days before an election, a requirement that was upheld by the Supreme Judicial Court in 2018.

Now, voting rights activists are asking lawmakers to let voters register at the polls.

According to the National Conference of State Legislatures, 17 states and Washington, D.C. allowed Election Day voter registration as of January 2019. Two other states have passed but not implemented it.

Studies have found an average increase in voter participation of 5% in states with same-day registration, according to NCSL.

Healey said there are an estimated 780,000 voting age adults who are not registered to vote, although many of them could become registered through automatic voter registration.

“We think it’s a common sense reform,” said Patrick Roath, vice chairman of the advisory board for Common Cause Massachusetts. “It helps everybody vote who’s already eligible to vote.”

Roath and Nancy Brumback, legislative director for the League of Women Voters for Massachusetts, said automatic voter registration will help, but it does not pick up people who are new to Massachusetts, who do not interact with the Registry of Motor Vehicles or MassHealth, or who have a mistake in their registration.

Brumback said today, if there is a problem with someone’s registration — for example, their name is spelled wrong or an incorrect address is listed — they have to vote on a provisional ballot. Then, election officials must verify that they are eligible. Early voting would let someone show proof of residency at the polls, then vote with a regular ballot.

The bill filed by Galvin and Rep. Angelo Scaccia, D-Boston, would allow someone to register to vote on Election Day by providing proof of residency and identity and signing an affidavit under oath affirming that they are eligible to vote. Lying on the affidavit would be a felony punishable by up to five years in a prison and a $10,000 fine.

Galvin said to ensure security, a system would need to be set up to connect all polling places — so if a person registers in one town, an official could make sure they did not already vote elsewhere, and could immediately remove them from the voter list of any other town.

Galvin also said there would need to be two people at every polling station focused on registering new voters, to avoid holding up a line of voters who are already registered.

The proposal is likely to raise questions about voter fraud. There have been occasional instances in Massachusetts already of people voting in two states.

But advocates say other states with same-day registration have not seen problems.

Brumback said most voter fraud is done through hacking or absentee ballots. “In-person voter fraud for all practical purposes does not exist,” she said.