Hawn's appearance has been rumoured for weeks.
Hawn elaborated on a story he has mentioned before: That in the 2006 election, someone called him and offered voter information cards that had been left in apartment building lobbies.
Hawn said it wasn't uncommon to find VICs in recycling bins in buildings, and that it also wasn't unusual for Chinese or Vietnamese people to receive two or three of the cards due to what he called the transposition of their names.
Hawn also brought up names of other MPs in the past who had also complained about the abuse of the voter information cards.
He said he was using these example to to attest that the potential for voter fraud is "absolutely clear." He added, "Election fraud does exist in Canada, We need to stay alert," he added. "People will also find a way."
Hawn also alluded to his former career as a fighter pilot, saying that at 30,000 feet you don't see much, but flying at ground level you see much more, likening the experience to politicians "on the ground" who see voting abuses.
Asked about a part of the new bill that would eliminate vouching, Hawn said he personally didn't see a problem with what he called "one-on-one" vouching if the identity of the person doing the vouching could be validated before a ballot was cast.
He also seemed to agree with Liberal MP Kevin Lamoureux that the voter information card could be used as ID, if the system of creating the date base for the cards could be scrubbed for errors.
At one point Hawn quipped about his responses to opposition MPs: "I hope I haven't been too supportive."
One of the more controversial provisions of the new bill is the complete elimination of the use of VICs as ID on voting day. VICs are mailed to every potential voter Elections Canada has managed to find an address for. Receiving a card means the recipient is on the list of voters, but must still provide photo ID in order to cast a ballot.
Bill Casey, a former Conservative MP from Nova Scotia who ended his career sitting as an Independent because of a dispute with the government, will also appear for an hour Thursday.
At the same time, at a Senate committee that is also studying the election reform bill, former B.C. elections chief Harry Neufeld is to testify.
Neufeld, who has previously appeared at the Commons committee, will focus on three contentious aspects of the bill.
In pre-released speaking notes, Neufeld says he will address a part of the bill that allows federal election candidates to appoint central poll supervisors to work an election.
Currently, candidates have the power to name deputy returning officers and poll clerks, but Neufeld notes the position of central poll supervisor is a more crucial job and should be filled by a neutral party, not a partisan. He also recommends that all election day workers should be hired on merit, not on political affiliation.