The Imam claimed Tarrant had been to the mosque three weeks in a row, dressed in traditional Pakistani clothing, so that he could get an accurate layout of the mosque.
The Imam also claimed Tarrant asked a worshipper if they prayed at the same time every Friday.
When asked by Newshub if he seemed familiar with mosque, the Imam replied "100 per cent".
Another worshipper claimed that his friend hugged Tarrant during a visit.
Newshub claimed that police found evidence that Tarrant's vehicle was outside the mosque.
But Christchurch police Superintendent John Price said the shooter did not physically enter the mosque; but believe he would have carried out a virtual tour.
READ MORE:
• Christchurch mosque shootings: Brenton Tarrant's shock guilty plea to murders
• Christchurch mosque shooting: Survivors attend pre-trial court hearing
• Christchurch mosque shootings: How's the city feeling one year on?
• Christchurch mosque shootings: Philip Arps loses appeal against strict prison release conditions
"Police have carried out an extensive investigation and there is no evidence to suggest that the gunman entered the Al Noor Mosque or its grounds prior to the March 15 attack.
"After police extensively reviewed CCTV footage as part of the investigation, it was found he had parked across the street before March 15.
"Police also believe he viewed an online tour of the mosque.
"While the matter remains before the court we are unable to provide any further information."
In a shock move last month, Brenton Harrison Tarrant admitted murdering 51 Muslims at two Christchurch mosques on March 15 last year.
The 29-year-old Australian entered the guilty pleas at a special, hastily-arranged High Court hearing in Christchurch on March 26.
He also admitted 40 charges of attempted murder relating to the two attacks at Masjid Al Noor and Linwood Islamic Centre on March 15 last year - and pleaded guilty to one charge of engaging in a terrorist act laid under the Terrorism Suppression Act 2002.
Tarrant was convicted on all charges and remanded him custody until May when lockdown restrictions would be relaxed and a new sentencing date will be set.