VICTORIA -- Those for and against changing British Columbia's provincial voting system to a form proportional representation will soon have a say as residents begin receiving referendum ballots in their mail boxes.

The debate started to heat up Tuesday in the legislature, with the Opposition Liberals calling the vote a "sham," but it was all cheers at an evening rally in support of the change side.

About 1,000 people attended a campaign-style event that featured speeches in favour of electoral reform by Green Leader Andrew Weaver and New Democrat Premier John Horgan.

"I firmly believe people want co-operation, not conflict," said Horgan. "We will not make progress as a society if we continue to battle ourselves over outdated ideas."

The premier told the crowd he is a late convert to proportional representation, but having his ideas constantly dismissed because he was not part of government convinced him to support electoral reform.

He said he voted against electoral reform in B.C.'s first referendum in 2005, but voted in favour in 2009 and made the current referendum a campaign promise in 2017.

B.C.'s two previous electoral reform votes failed.

"Pro Rep means exactly what it says," said Horgan. "If you get 40 per cent of the votes, you get 40 per cent of the seats."

Opposition Liberal Leader Andrew Wilkinson and Horgan spent much of Tuesday in the legislature challenging each other on the issue.

Wilkinson said Horgan is afraid to debate the topic, but Horgan said he's waiting for the event to be organized.

"This is what we get from a premier who hasn't got the guts to face the cameras because he's a coward about this manipulative referendum," he said. "This democracy has worked since 1871. Do not let these people opposite play games with your franchise and overrule your fundamental rights. It's a complete sham."

The referendum asks B.C. residents if they want to change the electoral system to a form of proportional representation or keep the current first-past-the-post method. A majority of 50 per cent plus one is needed to change the system.

Elections BC said it mailed 3.3 million referendum ballots to registered B.C. voters this week. The deadline to return the ballots is Nov. 30, and a vote result is expected several weeks later.

Packages are also being sent internationally to registered voters who are temporarily away from their homes in B.C.

Weaver, whose Green party also supports electoral reform, told the rally the referendum offers voters a unique opportunity to change they way they elect their governments.

"We now are at a pivotal moment," he said. "We have the opportunity to change the system to make it more inclusive, to ensure every vote counts and to finally have a system that lets people vote for what they want without fear of getting what they don't want."

The Greens, which have three members in the legislature, reached an agreement after the election last year to support a minority NDP government. Part of that deal included holding an electoral referendum this year.