Raj Sherman, the newly-elected leader of the Alberta Liberal Party, became a member of the party's caucus Monday after accepting an formal invitation to join the official opposition.

"It's truly a privilege to and an honour for me to stand here today with my new caucus colleagues, ready to stand up for what Albertans value," Sherman said at the Alberta legislature in his first formal news conference as party leader.

Sherman was flanked by all eight members of the Alberta Liberal caucus, including outgoing party leader David Swann, and leadership contenders Laurie Blakeman and Hugh MacDonald.

Sherman, an emergency room doctor and former Progressive Conservative MLA, became leader Saturday after capturing nearly 55 per cent of the vote on the first ballot.  Since he was sitting as an independent MLA, Liberal Party rules didn't allow him to join caucus until he was invited by Liberal MLAs.

Questions linger about vote

Sherman was elected to represent the riding of Edmonton-Meadowlark in the 2008 provincial election. He became the government's parliamentary assistant to the minister of health and wellness but was ousted from the Tory caucus last fall after criticizing his party's handling of emergency-room wait times in Alberta.

Although he was elected as a Tory, Sherman says his switch to the Liberals is supported by his constituents.  

"They said, 'We want you to join the Alberta Liberal Party,'" he said. "Not one constituent said 'Go back to where you were.'"

While MLAs presented a united front at Monday's news conference, there are still questions about the leadership vote.

In a controversial move, the party opened up the vote to all Albertans, who could cast their ballots online, in person or by phone. By Friday, 28,985 people had registered to vote.

Sherman's campaign signed up more than half that number, by using an automated phone-out system, which allowed people to join by punching a number.

MacDonald says he still has questions about problems people had accessing the voting system and a 1,900-name discrepancy in the number of eligible voters.

"Those are valid questions that a guy wants answers for," MacDonald said. "And it's reasonable."

MacDonald said he voted in favour of allowing Sherman into the Liberal caucus.