New Zealand Prime Minister John Key on Monday announced details of the government's earthquake support package for Christchurch businesses and workers.

Key said the government originally considered a four-week interim package, but decided to make it six-weeks to give it time to come up with a longer-term package.

The first part of the assistance package is an earthquake support subsidy to help employers keep paying wages.

It has wider criteria than the subsidy after September's quake.

Ineligible businesses are multinational companies, nationwide chains and those with insurance cover.

The subsidy is 500 NZ dollars (375 U.S. dollars) a week for each full-time employee and 300 NZ dollars for each part-time employee.

Key says the subsidy is intended to keep people in jobs and support businesses as they look to recover from the effects of the earthquake.

The second part of the package is job loss cover for those who consider their business is no longer viable, and those who can't contact their employees.

The job loss cover is 400 NZ dollars in the hand a week to help full-time employees during their transition to another job or welfare assistance. For part-time employees, the cover is 240 NZ dollars.

This cover is universal, not means tested and available immediately.

Key said the biggest contribution people can make to the recovery is to go back to work.

Key said he is confident Christchurch can be rebuilt to a safe standard.

Key said the earthquake has huge financial implications but thinks the country can afford it.

He said an increase in the Earthquake Commission levy to possibly three times the current level is the preferred way at present to rebuild the city.

He said the Cabinet will consider reviewing the rules on earthquake insurance, which could mean raising the maximum payout of 100,000 NZ dollars.