She echoed Sue Moroney in accusing the Government of being "undemocratic" in its response.
A Plunket spokeswoman said the organisation believed that the bill, the Parental Leave and Employment Protection (Six Months' Paid Leave) Amendment Bill, deserved to be debated.
"Babies need the chance to bond with their mum without pressure on her to return to work or manage on a suddenly reduced income."
Mr English said the Government was still $10 billion off clearing its overdraft and if the bill passed it would have to be funded through borrowing.
He believed the public would have a similarly ''pragmatic'' approach.
Sue Moroney accused Mr English of being the "Minister of Arrogance."
"To say the country can't afford it is a bit rich coming from the same person who can find $2 billion a year for tax cuts for the top 10 per cent of income earners, $100 million in fees to investment banks to prepare the sell-down of our state-owned assets, and $50 million to 'progress' a cycle-way that, from all accounts, is going nowhere," she said.
She said his suggestion that it was a project designed to win votes showed "a blatant disregard for the will of Parliament but smacks of arrogance."
New Zealand First leader Winston Peters said his party had not discussed the bill, which was drawn out of the private members ballot last week, and neither National nor the bill's sponsor had discussed it with him.
"What is happening is government through media columns. It actually does not work in practice."