TORONTO - Embattled MP Ruby Dhalla is to appear Tuesday before a federal parliamentary committee and defend herself against allegations that foreign caregivers working at her family's home were mistreated.

Dhalla's testimony will follow that of the two caregivers at the heart of the allegations against her, including claims that she withheld the passports of the caregivers and paid them only a fraction of the minimum wage.

Dhalla has strongly denied allegations and called the allegations an attack on her political career.

It was Dhalla's wish to testify Tuesday, said her lawyer Howard Levitt, adding she "pushed and lobbied hard" to ensure it occurred.

"She wants to defend her reputation, she does not want this to stretch to months from now," Levitt said.

"What she's going to say is that it's absolutely improper that she's being attacked with all these allegations that have nothing to do with her; she was not the employer of those caregivers she had nothing to do with it at all."

Her appearance bumps Ontario Labour Minister Peter Fonseca, who was asked to participate in the proceeding and was expected to testify at the standing committee for citizenship and immigration in Ottawa on Tuesday.

The two caregivers told their stories to Fonseca and Ontario Education Minister Kathleen Wynne during a roundtable discussion last month, and critics have accused the two ministers of staying quiet because the complaints involved a prominent Liberal MP.

Magdalene Gordo, 31, and Richelyn Tongson, 37, say they were hired in early 2008 to work in Dhalla's family home in Mississauga, Ont., to care for her mother.

A third caregiver, Lyle Alvarez, has claimed she was severely overworked and underpaid as well.

"I look forward to being able to present in front of that committee all that I've been hearing from live-in caregivers and what they've been able to share with me around a flawed and broken federal program," Fonseca said earlier Monday, adding that his testimony will not deal with specifics about Dhalla's case or anyone else's.

He has repeatedly tried to blame federal Immigration Minister Jason Kenney for problems with the program than brings live-in caregivers to Canada.

"I've always wanted to stay focused on what we can do for these vulnerable workers and ensure that protections are in place there for them," Fonseca said.

Fonseca's office said the committee was in the end unable to accommodate him Tuesday, adding no new date had yet been set.

He was originally asked to appear Thursday.

Wynne has also been asked to speak to the committee but has declined, calling it a labour issue.

"It was an invitation to come and speak about the live-in caregiver program, and Minister Fonseca has carriage of that file," Wynne said. "He'll be going representing the government."

The Progressive Conservatives and New Democrats have accused the two ministers of staying quiet because the complaints involved a prominent Liberal MP, and have repeatedly asked for Fonseca's resignation.

Opposition Leader Bob Runciman said Monday he hopes the committee pushes Fonseca on what he calls "moral and ethical failures" -- accusations he believes the province is trying to shield Wynne from.

"The bottom line here is to protect Wynne -- she's the important minister in this twosome," Runciman said. "He's expendable and they're going to send him up there to be the sacrificial lamb. And all he's going to do, apparently, is spin the same lines he's been spinning in here, which is saying really nothing about what transpired and why they made the decisions they made."

Regardless of Fonseca's plans, NDP Leader Andrea Horwath said she believes the committee will bring up specifics about Dhalla's case.

"Both of these ministers were derelict in their duty in terms of making sure that the laws in the province were upheld and that they did proactive work around having these issues investigated," she said.

In his first day back in the legislature since the controversy broke last Wednesday, Premier Dalton McGuinty said he commended Fonseca and Wynne for hosting the roundtables and taking the time to meet with live-in caregivers and hear their stories.

He has lashed out at the opposition parties and reporters for focusing on the allegations against Dhalla when the ministers heard about 30 similar stories from caregivers, calling opposition demands to jail Dhalla "entirely inappropriate."

"We think the appropriate thing to do in the circumstances is to apprise those women of their rights, to encourage them to follow up should they feel it important to do so," McGuinty said Monday.

Dhalla has given up her post as Liberal multiculturalism critic while she seeks to clear her name.