The New Zealand cabinet on Monday made an initial 5 million NZ dollars (3.5 million U.S. dollars) contribution to the mayoral fund set up to help those affected by the earthquake in New Zealand's South Island.

The welfare fund is to assist people not covered by other agencies such as Work and Income.

Prime Minister John Key said Cabinet will make 94 million NZ dollars from the emergency works budget available immediately so work can start on fixing roads.

He said the 5 million NZ dollars marked just the start of the government's financial contribution, and the cost of restoring infrastructure will run into hundreds of millions of dollars.

Demolition work has got under way in central Christchurch to remove buildings devastated by Saturday's 7.1 magnitude earthquake.

Heavy machinery began pulling down condemned buildings to make the city safer earlier on Monday afternoon.

Lines company Orion said people are putting themselves at risk by demolishing quake-damaged houses before they have been completely removed from the power network.

Christchurch Medical Officer of Health Ramon Pink said gastroenteritis is inevitable in the city if people do not take precautions.

Pink said damage to water and sewerage systems raises the risk of gastroenteritis, and he has had unconfirmed reports of 12 cases since the quake.

The New Zealand army is now in control of central area of South Island's largest city of Christchurch as the clean-up continued following the earthquake.

Two contingents of 80 soldiers began 12-hour rotations from 8 a. m. Monday.

Meanwhile, 80 police reinforcements brought in from Auckland on Saturday will be replaced later on Monday with officers from Wellington and Timaru.

A state of emergency in Christchurch has been extended until Wednesday.

Another curfew in the city was in place on Monday, from 7 p.m. - 7 a.m., for the public's safety.