The Jatiya Party won 33 seats — 20 without any contest — in the polls boycotted by the Bangladesh Nationalist Party-led opposition alliance.
Ershad on Saturday evaded media after he was sworn in, two days after his fellow party MPs took oath under the leadership of Raushan.
Witnesses said he entered parliament through a route used by the President, Prime Minister and Deputy Leader of the House.
No Jatiya Party leader was seen accompanying Ershad as he came out of hospital, where he was being treated to “regain his fitness”, to go to parliament.
Earlier, Raushan said she would function as opposition leader, fuelling speculation about the stand of her husband.
