The Liberal Party has announced there will be 294,002 voters who can potentially vote in the Liberal leadership race in April, a total that includes regular party members as well as those in the new "supporter" catergory.

On Monday, the campaign team for Justin Trudeau revealed that it had signed up 150,000 supporters for Trudeau, without offering any proof of that number.

The seven other candidates will not say now many supporters they have gathered on their own websites, although Joyce Murray said she had collected "tens of thousands" and Martha Hall Findlay wrote on her website, "I am excited that our campaign has been able to directly sign up thousands of new Liberal supporters over the past few weeks."

Supporters could also sign up on their own through the Liberal Party's website.

The party must sift through the names and addresses of supporters to check if they are indeed entitled to cast a ballot during voting week which takes place April 7-14.

A senior party official said the vetting process will continue for the next five weeks, and could continue even through voting week. A Liberal supporter could be challenged at any time, he said.

For the first time in the history of the Liberal Party, a type of voter called a supporter can cast a ballot without having to join the party or pay a membership fee. The system was designed to open up the leader selection process to a larger swath of the population, somewhat the way party leaders are chosen in the U.S. during primaries.

The Liberal Party is handing a lot of power over to non-members. A document prepared for the Liberals’ Roadmap to Renewal convention in January 2012 said: "As a Liberal supporter, you will lead this movement. You will bring strength in numbers. You will shape our values and our ideas. And, when confirmed as eligible, you will make our most important choice: who will represent us as Liberal leader."

The danger is that it's so easy to sign up as a supporter that members of other parties may try to join, or people using fake names and bogus emails may attempt to become supporters in order to skew the vote.

'Fluffy the cat' can't vote

Monday a spokesperson for the Liberal Party said that the vetting process will filter out anyone who signs up as "Fluffy the cat," and will eliminate duplicate signups. As well, the provincial and territorial party associations will lend a hand in vetting submissions.

A senior Liberal official said vetters will use an automated system and try to match the supporters’ names against the Election Canada's voters list which is available to all political parties. It will also look for "clumps" — such as a number of supporters from one address — and will do spot audits of representative samples of supporter sign-ups.

The official admitted that the party can't determine if supporters belong to another political party, but said supporters must declare that they are not members of another party, something he described as a "solemn declaration" with legal weight, and that not telling the truth could be "arguably committing fraud."

However, he said, "No leadership process is without risk — if people want to try to defraud the system, they can."

Liberal MP Sean Casey, who is supporting Trudeau, said he thinks the 150,000 figure for Trudeau may be "lowballing the numbers," which he considers a safer strategy than overestimating the figure. Liberal MP Wayne Easter, also a Trudeau supporter, thinks Trudeau's tally is "well north" of 150,000.

Easter believes there may be a lot of duplicate sign-ups and said he knows people who were already Liberal Party members who became supporters, not realizing that they didn't have to. The Liberal Party said Monday that it was "scrubbing" the list, and may have gotten rid of many duplicate names.

Everyone who signed up as a supporter must take an extra step, and register with the party by March 14 so they can vote in the leadership race. There's a huge social media effort going on urging supporters to make sure they contact the party and register before it's too late.

The lists of supporters, including Trudeau's, will being given to all the candidates on March 14 so that they can contact the supporters, and, in some cases, submit challenges about the identity or eligibility of supporters. A final list will be drawn up and eligible voters will be given a PIN between March 25 and April 6.

The new leader of the Liberal Party will be announced April 14.