The man accused of the Christchurch terror attack is expected to enter pleas to nearly 100 charges next week.

Brenton Harrison Tarrant, a 28-year-old Australian national, has been charged with murdering 50 Muslim worshippers at two city mosques on March 15 this year.

The alleged gunman is due back in court next Friday where it is anticipated he will appear from custody via audio-visual link and also, through his defence counsel Shane Tait and Jonathan Hudson, enter pleas to the charges.

It's also anticipated that during the short and largely administrative hearing, the Crown will also formalise the laying of another murder charge, two additional attempted murder charges, and a charge under the Terrorism Suppression Act 2002. That will mean the alleged gunman will face a total of 51 murder charges and 41 attempted murder charges, along with the terrorism charge.

At the defendant's second court hearing at the High Court in Christchurch on April 5, mental health reports were ordered to explore whether he is mentally fit to enter pleas to the charges.

His defence team asked for mental health experts to assess the accused under section 38 of the Mental Health Act.

Justice Mander ordered two health assessors' reports and stressed that the move was "normal procedure" and an "entirely ordinary and regular step" to be taken at this stage of the judicial process.

Nothing should be read into the ordering of the reports, he added.

It's expected the reports will have been completed and made available to the courts by next Friday's court appearance at the Christchurch Justice Precinct.

Around 50 family members and survivors of the Al Noor Masjid and Linwood Islamic Centre came to court last time to witness proceedings, and several will be expected to sit in the public gallery next week.

There will also be a large number of national and global journalists in court, along with a heavy security and police presence.