New Zealand’s deputy prime minister says the man accused of killing 50 people in two mosques will spend the rest of his life in isolation in prison and called for solidarity to eradicate “hate-filled ideologies”.

Winston Peters was speaking at an emergency session of the 57-member Organisation of Islamic Co-operation’s executive committee called by Turkey to combat prejudice against Muslims after the attack.

Mr Peters’ attendance comes amid controversy sparked by Turkish President Recep Tayyip Erdogan who, at election campaign rallies, has been screening video clips of the attack, despite efforts by New Zealand to prevent the video’s spread.

Mr Erdogan also drew Australia’s anger for comments suggesting Australians and New Zealanders with anti-Muslim sentiments would be sent back in coffins like their ancestors who fought against Turks in the First World War Battle of Gallipoli.

Mr Peters took a conciliatory tone on Friday, welcoming comments by Turkish foreign minister Mevlut Cavusoglu, who said at a news conference at the end of the OIC meeting that Australians and New Zealanders visiting Turkey would be greeted at Gallipoli remembrance ceremonies next month with the same welcoming hospitality “as they always were”.

Mr Peters said: “We are returning home to New Zealand with a grateful assurance that our people will come here to commemorate Anzac and will be as welcome as they always were.”

He said he did not discuss Mr Erdogan’s use of the footage with Turkey’s foreign minister or president.

“I did not see any sound, peaceful purposes in raising it,” Mr Peters said, adding that they had received “very assuring information” from the Turkish presidency.

Mr Peters told representatives of Muslim nations: “No punishment can match the depravity of (the gunman’s) crime but the families of the fallen will have justice.”

He also screened moving photographs of New Zealanders mourning the victims.

Brenton Tarrant, a 28-year-old Australian, was arrested and charged with murder. The gunman livestreamed the attack and released a manifesto describing his white supremacist views and how he planned the shootings.

The OIC urged all countries to refrain from statements and policies that associate Islam with terror and extremism. It also demanded that March 15 – the day of the Christchurch attack – be marked as the International Day of Solidarity Against Islamophobia.

Addressing the OIC meeting on Friday, Mr Erdogan praised New Zealand prime minister Jacinda Ardern, saying her “reaction, the empathy displayed, and her solidarity with Muslims” should serve as an example to all leaders.

He condemned populist politicians who he said encouraged attacks on Muslims and refugees.

“Politicians who pave themselves the road to power by alienating Muslims and creating enemies out of refugees must pull themselves together.”

He also called for neo-Nazi groups to be considered terrorists.

He said: “If we don’t show our reaction in a strong manner, the neo-Nazi virus will engulf the body even more. If we don’t raise our voices, Western governments will not disrupt their comfort.”