UPDATED 12.46PM: The move to charge interest on legal aid is being blasted as an appalling idea which doesn't work.

LISTEN: Tony Bouchier - Legal aid changes

About 20 percent of people who get legal aid are charged fees for the service and since last year the Government has been charging interest on unpaid fees.

Labour MP Jacinda Ardern says some of them can't get legal aid because they share equity in a home with a violent partner.

"We think the minister needs to look at ways to make protection orders accessible," she says. "There are options to do that and that at least would remove that barrier."

Ardern says even when family lawyers offer cut-rate services, many people find it too costly and difficult to get a protection order.

Ardern understands hundreds of people are going without protection orders because the legal process is too difficult and expensive. They are "predominantly women in devastating situations, fearful of their lives, who are having to take into account whether or not they have the financial ability to get protection."

Criminal Bar Association president Tony Bouchier says most people can't afford to pay, and only a fraction of the interest has been paid so far.

"The idea that you charge those people for those legal services and then add interest on top is just simply wrong," he says.

"Nearly six million dollars in interest has been charged and less than one hundred and fifty thousand dollars has been collected of that interest."