Gerrard, the lone Liberal sitting in the legislature, has told party members in an email that it is vital that they rally around new leader Rana Bokhari.
A small but vocal group of Liberals has criticized Bokhari and the party executive since she became leader last October.
They say the party is ignoring the grassroots and taking power away from the board of directors.
The latest accusations come in a letter sent to several Liberals by board member Valerie Thompson and which says the leadership is undemocratic.
The Liberals are preparing for their annual general meeting next Friday in Winnipeg.
Gerrard's email tells party members to stop arguing.
"As I well know from my years as the Manitoba Liberal leader, it is vital for Liberals to rally their support around our leader and to be ready to consider improvements to our organization and to our efforts. We must move forward together," Gerrard wrote.
"Right now we are building steam as the polls show more Manitobans looking to vote Liberal. Keeping that momentum is paramount. It will require a strong and unified effort to succeed. Let us stay vigilant in our efforts ... and let us strongly support the leaders we elected as we move forward.
When contacted by phone by The Canadian Press, Thompson said she was simply passing on a letter written by other board members. She would not identify who they were and hung up.
"It is with sadness today we are writing to tell a story of a party that has seemed to suspend democracy and in essence fired the board of directors. A party controlled by a few instead of by the people," says the letter.
Other Liberals who have come out against Bokhari include Bob Axworthy, who finished a distant third in last year's leadership race, quit the party and has since rejoined. Earlier this week, Shane Nestruck, president of the party's Fort Garry-Riverview constituency association in Winnipeg, made similar accusations.
The turmoil has hit the Liberals just as the party appears set to emerge from two decades in the political wilderness. It garnered 7.5 per cent of the vote and one legislature seat in the 2011 election, but recent opinion polls suggest support has topped 20 per cent as the NDP government's popularity has shrunk.
Among the concerns of Bokhari's opponents are several proposed changes to the party's constitution that are to be debated next weekend. They would reduce the size of the board of directors and allow for less frequent board meetings.
Gerrard called for a calm discussion.
"Let's have an open and thoughtful dialogue that respects each other and our party rules. All members present will have a chance to vote on any changes, as should happen with a democratic assembly.
"Once the results are in, we should then stand behind those results, for that is how democracy works."