It is set to be a busy week for New Zealand politicians, as changes to gun legislation are set to become law by April 12.

The Government has rushed through legislation that will ban semi-automatic weapons, amongst other changes, in response to the Christchurch terror attack.

50 people were killed after a single gunman used military-style weapons to attack two mosques in Christchurch last month. 

There has been criticism that the legislation has been rushed through, as the select committee process has been reduced from the standard six month time period. 

Otago Law Professor Andrew Geddis told The Weekend Collective says that this time, the select committee process will be reduced to just one week.

He says that the six month time frame is so laws can be considered carefully.

"The six month period allows for people to actually know an area, as normally parliament legislates in an area where lots of people in the community have expertise they can feed into the process." 

There are concerns that the rushed law change could allow room for mistakes. 

The Herald on Sunday found several examples of firearms or devices designed to get around prohibition on semi-automatic weapons that could be imported by gun enthusiasts. 

Police Minister Stuart Nash says that this initial law change is the first step in what could be future changes. 

"The second phase of changes, which we hope to introduce in June, will address the need to future-proof our gun laws. We need to make it easier for future Parliaments to respond quickly to further technological and social change."

Geddis says that that is possible, as there is a "Henry the Eighth clause" that will allow them the freedom to alter the law. 

"If and when gun manufacturers start playing with the way they make guns to get around whatever definitions are put into this act, the Government can change the definitions of firearms without having to come back to Parliament." 

He says this shows that the Government understands this is an area that will constantly change. However, the clause could raise concerns about the ease with which future Governments can change the law. 

"We want MPs in Parliament to change the law, not Ministers." 

Secretary of the Council of Licensed Firearm Owners Nicole McKee agrees, telling the Weekend Collective that the Government does not need to rush as there is already a moratorium in place on the guns. 

"Why not use this moratorium time to actually get some effective legislation so we can actually go about the Government's intent properly?