OTTAWA -- A New Democrat MP has quit the caucus over what she felt was an excessively pro-Israel stance on the current conflict in Gaza and demeaning party demands to keep quiet and toe the line.

Sana Hassainia, who represents the Montreal-area riding of Vercheres-Les Patriotes, was specifically critical of NDP Leader Tom Mulcair in a blog post that appeared online Wednesday.

In an interview with The Canadian Press, Hassainia said her unhappiness with the leader and party began after the 2012 leadership race. She says she was removed from a Commons committee and relegated to the backbench because she had supported Mulcair's rival Brian Topp.

But "the straw that broke the camel's back" Hassainia says was Mulcair's distinctly pro-Israel stance, despite the heavy civilian casualties in the Gaza Strip this summer. She said she could no longer remain silent in the name of loyalty to the leader and electoral strategy.

"I said to myself, my God, we're a social democratic party, and we're saying that Israel has the right to defend themselves against a people that are completely powerless," said Hassainia, suggesting she was not alone in that viewpoint.

"When there's such a huge difference of opinion between MPs and their leader, are they supposed to support that position or are they going to evolve with the situation?"

Hassainia, a Tunisian-born Muslim, underlines that she recognizes Hamas is a terrorist organization, but feels it is civilians and not Hamas that are bearing the brunt of the conflict.

NDP sources fired back saying Hassainia has never before voiced concern over Mulcair's position on Israel and accused her of simply looking for an excuse to cover the fact that she rarely shows up for work.

Mulcair, speaking at a news conference in Toronto, said the party has never made a secret of its position on the Middle East.

"The NDP has a long-standing position in favour of the two state solution in the Middle East -- a safe, secure state within negotiated borders for Israelis and a safe, secure state within negotiated borders for Palestinians," he said.

"Sana in her note made it clear she doesn't agree with that. That's been our position for many years, it was Jack's position, it's mine, and so she's decided that she doesn't want to sit with us. That's her choice."

So far this year, Hassainia has the worst voting record of all MPs, showing up for only 8.7 per cent of votes in the House of Commons.

Since winning election in 2011 as part of the so-called "orange wave" that swept Quebec, the 39-year-old has given birth to two children.

A source close to Mulcair said the party bent over backwards trying to accommodate Hassainia's need to be with her young children, even letting her use the leader's office to breastfeed. But still the party's whip, Nycole Turmel, was frustrated in her efforts to get Hassainia to show up for votes and perform other parliamentary duties.

Hassainia acknowledges she refused to attend evening votes in the Commons after her second child was born in June 2013, feeling she was no longer ready to sacrifice her family life. She accuses the party of doing next to nothing to help her balance the demands of Parliament and the two toddlers at home.

"For them to come out with my attendance record, I find that petty," said Hassainia. "A party that talks about work-life balance and wants to recruit new women candidates for 2015, and young women who could have children, if you want that to happen you have to given them tools to also bloom at home."

Hassainia has not made a decision whether she will run in 2015.

Mulcair has been more unequivocal in his support for Israel than previous NDP leaders but he's walked a fine line on the conflict in Gaza.

He has supported Israel's right to defend itself against Hamas missile attacks but has simultaneously pushed the federal government to help Palestinian children injured by Israeli missiles.

-- With files from Jennifer Ditchburn