Amid tight security, Prime Minister Jacinda Ardern will join mourners near the Al-Noor mosque, one of the two places of worship targeted in last Friday’s shootings.
Later a mass burial will take place for many of the victims.
Fifty people were killed and dozens more wounded in the attacks.
Australian Brenton Tarrant, a self-proclaimed white supremacist, has been charged with one murder and is expected to face further charges.
On Thursday Ms Ardern announced a ban on all types of semi-automatic weapons.
What will happen on Friday?
Thousands are expected to gather in Hagley Park, near the Al-Noor mosque, to mark Friday’s national day of reflection for the victims.
The Muslim call to prayer, or adhan, will be broadcast on national television and radio at 13:30 (00:30 GMT) and be followed by the two-minute silence.
“We are so happy that this prayer will be broadcast to the entire world so that everyone can be part of it,” said Mustafa Farouk, president of the Federation of Islamic Associations of New Zealand.
Many mosques across the country are expected to open their doors to visitors and human chains will be formed outside some in symbolic acts of protection and solidarity.
Victims of the Christchurch shootings
Fifty people lost their lives in the shootings at two mosques in the city
Ms Ardern has encouraged as many New Zealanders as possible to use the day to pause and reflect.
“I know many New Zealanders wish to mark the week that has passed since the terrorist attack and to support the Muslim community as they return to mosques,” she said.
“How we choose to reflect during the silence will be different for each of us. Everyone should do what feels right for them, wherever they are – at home, at work, at school.”
One social media campaign has urged non-Muslim women in New Zealand to wear a headscarf for the day.
Meanwhile, government officials worked into the night to prepare the mosque and the bodies of victims for Friday’s mass burial in Christchurch.
One person who took part said: “All the bodies are washed. We finished around 1.30am. It was our duty. After we finished there was a lot of emotion, people were crying and hugging.”
What is the gun ban?
Ms Ardern announced a ban on all types of semi-automatic weapons and assault rifles following the Christchurch attacks.
She said she expected new legislation to be in place by 11 April, saying: “Our history changed forever. Now, our laws will too.”
“Six days after this attack, we are announcing a ban on all military style semi-automatics (MSSA) and assault rifles in New Zealand,” Ms Ardern said in a news conference.
“Related parts used to convert these guns into MSSAs are also being banned, along with all high-capacity magazines.”
An amnesty has been imposed so the owners of affected weapons can hand them in, and a buy-back scheme will follow.
The buy-back could cost up to NZ$200m ($138m; £104m), but Ms Ardern said “that is the price that we must pay to ensure the safety of our communities”.
Ms Ardern has also announced that a National Memorial Service for victims is being planned for next week.