Parliament has unanimously passed a bill creating a public holiday for the Christchurch earthquake commemoration, although some MPs think next Friday is too soon.

Labour Minister Kate Wilkinson introduced the Canterbury Earthquake Commemoration Day Bill and it passed all its stages today.

She said she expected tens of thousands would attend the commemoration in Hagley Park.

"This will place an unexpected cost on businesses ... but there is no getting away from the fact that the earthquake is the region's worst ever tragedy," she said.

"The wounds are there for all to see. This is a day for people to come together and grieve together."

Police Minister Judith Collins paid tribute to the victim identification teams working in Christchurch.

"I'm fully aware that we may never have all the names of those who have lost their lives, such has been the devastation that has been wreaked on some individuals," she said.

"The police are doing their very best to get absolute accuracy in the remains of those deceased so they are returned to their correct families."

Labour's Trevor Mallard, and several of his colleagues, said they fully supported the bill but thought more time should pass before the commemoration.

"My personal view is that it might have been better to wait a little while until we had an understanding of who had actually died, at least as good as we are ever going to get," he said.

"I know of a close friend who has died but his name has not been released."

Prime Minister John Key told reporters in Christchurch the length of time before holding the commemoration had been considered, and he thought that if it was too long people would get frustrated because they had not had a proper opportunity to mourn.

The Manufacturers and Exporters Association (NZMEA) said it was too soon.

"Many of the quake victims have not yet been identified, businesses are still trying to restore their production, and schools and other services are not yet fully up and running," said NZMEA chief executive John Walley.

"It is too early for this sort of discretionary disruption."

The holiday is for Canterbury only, covering the same area as the Christchurch anniversary holiday.

The usual employment law provisions will apply.