A leaked Law Commission paper has questioned whether a new measure to allow police to issue "on-the-spot" protection orders for up to five days to prevent domestic violence is necessary.
The internal paper says it is "doubtful" if the orders are necessary because the threshold required is very close to that which would allow an arrest.
The law change will allow police called to domestic arguments to immediately issue an order requiring a person to stay away from the house for up to five days if it is necessary to ensure the immediate safety of another person in the household.
The paper to the commission's internal legislation advisory committee was leaked to blogger No Right Turn and reveals concerns about the new police power.
It says there should be provisions for urgent applications to have such an order set aside or to appeal against it. The five-day period was difficult to justify, especially because of the serious consequences of such an order. The paper says such an order should last only for the time required to make an application for a protection order from the Family Court - usually the next day, or two days at a weekend.
The bill was introduced under urgency late last year as part of National's 100-day plan.
As well as prohibiting a person from entering the home or trying to contact the person at risk, the new power will supersede any court orders allowing access to children for the period it lasts. An order can be made even if the potential victim objects to it.
Police Association head Greg O'Connor disputed that the power applied only to the same cases in which police could make an arrest.
He did not expect it to be used often because police did arrest if there was evidence of violence, such as an admission from one of those involved or a witness statement.
However, there were cases in which there was not sufficient evidence to arrest, but a reasonable certainty of abuse or concern that future abuse would happen.
"It will protect the very people who are most vulnerable - the ones who are too afraid to make a complaint."
Justice Minister Simon Power, who introduced the legislation, would not comment on the commission report, but said he looked forward to seeing the Law Commission's submission to the select committee.
Council of Civil Liberties chairman Michael Bott said the Law Commission's concerns over the inability to challenge the order were valid.
"What you have is the police who are an agent for law enforcement also acting as a prosecutor and a judge at the same time potentially by issuing an order prohibiting association without the right to a fair hearing."
The bill is before Parliament's justice and electoral select committee and public submissions close on February 27.