Last week's 6.3 magnitude earthquake unearthed a time capsule under the toppled statue of one of Canterbury's founding fathers, Christchurch Mayor Bob Parker said today.
Mayor Parker said rescue teams discovered the capsules while working near the destroyed statue of pioneer John Robert Godley.
The copper capsule and broken bottle were discovered at the top of the stone plinth where the statue used to stand, at 8am today.
They are believed to have been placed there when the statue was first erected in 1867.
Inside the bottle was a handwritten note in English that museum experts planned to unravel and read.
Canterbury Museum director Anthony Wright said it was a wonderful discovery amid all the sad news of the earthquake. He said he had no idea the items were all there.
They were discovered by a crane worker who was on top of the three metre-high plinth to see if the statue could be erected again - if only in a temporary way.
Mayor Parker said he believed that inside the time capsule were documents outlining the vision of the city.
"Why they came here, what was their vision."
The plan was to rebuild the statue and replace the artefacts where they were originally found, Mayor Parker said.
Police told the media conference that the death toll from the Christchurch earthquake was likely to be about 240.
Superintendent Dave Cliff told reporters the death toll remained at 154, after more bodies were found overnight. Three of the recovered bodies had been found in the PGC building.
But Mr Cliff said the number of dead was expected to rise. He said a figure of around 240 was "solidifying" but could still change.
Police would officially release the names of at least three more victims later today, he said.
Mr Cliff warned that it was not going to be possible in all cases for the bodies of dead - some of which had received horrific injuries - to be returned to families.
Identifying victims was "really emotionally charged and draining work", he said, and the process took time.
But Mr Cliff reiterated that the process was "absolutely robust" and was the same as used overseas.
Russell Wood from the Fire Service said he had toured the Pyne Gould Corporation building last night and that Urban Search and Rescue (Usar) workers at the site believed they would find more victims.
In a statement, police said there would be a controlled felling at the top of the building due to safety concerns about its stability.
Mr Wood said 30 cubic metres of concrete had been pumped into the base of the Hotel Grand Chancellor building yesterday to stabilise it so that Usar workers could enter it.
A key wall in the Christchurch Cathedral, where up to 22 bodies still lay, would be shored up today to allow better access for the Usar teams, he said.
Mr Wood said recovery efforts at the CTV building remained a daylight operation only.
Foreign Minister Murray McCully said hundreds of rescue workers and millions of dollars in overseas aid had poured into Christchurch in the wake of last week's 6.3 magnitude earthquake.
More than 900 international personnel from 12 countries are now working with New Zealand search and rescue teams in Christchurch, Mr McCully said.
Australia had been the biggest contributor to the rescue effort, he said.
It had sent 142 Urban Search and Rescue (USAR) workers from New South Wales and Queensland, 323 police officers, a 23 person medical team, three dogs to sniff out survivors and a 75-bed field hospital.
The United States sent 80 USAR workers and 40 tonnes of equipment and the United Kingdom sent 64 USAR personnel.
That generosity was matched by Japan, China, Singapore and Taiwan, which each sent USAR teams and search and rescue dogs.
Japan also sent a team of four counsellors, four fingerprint experts and an interpreter, while Singapore has 116 Defence Force personnel manning the security in Christchurch.
The recovery operation in the quake-hit city will also been bolstered by 1000 sheets of reinforced plastic, 1000 blankets and about 50 power generators expected to arrive from Korea on March 3.
Japan will donate 1000 plastic sheets and 2000 six litre water tanks. Australia is sending sanitation resources including camp toilets.
Steve Brazier, acting national co-ordinator for the Civil Defence operation told media 66 per cent of the city had water.
He said there were 67 tankers in areas which did not have water and desalination plants were being organised, but he said it would be "some weeks" before water was fully restored to the city.
About 500 people were in the city working on repairing water infrastructure today, he said.
"There are many breaks but there are many people who are really dedicated to getting these things fixed."
Mr Brazier said without water, there was no sewerage and the aim was to get one chemical toilet into every house without a toilet after the earthquake.
In the meantime, Mr Brazier suggested residents without toilets use plastic bags in their existing toilets.
Civil Defence said all water in Christchurch would be chlorinated today in an effort to combat contamination from broken sewers and waste water pipes.
The treatment is likely to continue for months while the city's infrastructure is restored, it said in a statement.
"Chlorine is a highly efficient disinfectant, and adding to public water supplies helps to kill disease-causing bacteria that may exist in the water or in transport pipes."
The chlorination is expected to be an issue for people receiving dialysis treatment. A free-phone dialysis helpline has been set up at 0800 881919.
Aftershocks are continuing to shake Christchurch with the latest a 4.3 magnitude earthquake at 9.10am.
GNS Science reported the earthquake was centred 10km east of Lyttelton at a depth of 2km.
GNS Science seismologist John Ristau said this morning's large and shallow aftershock could have pushed earthquake damaged buildings to breaking point.
The Geonet website has already received reports of damage and slight damage in its wake.
"If you have something that's ready to topple then all it takes is a little push.
"Depth plays a huge factor in how strongly an earthquake is going to be felt. Just a few kilometres of depth can make a huge difference."
Mr Ristau said the number of large aftershocks in Christchurch was trending downward.
It was encouraging that this morning's quake came more than 24 hours after a 4.1 aftershock that hit 10km south-east of Christchurch at 7.55am yesterday, he said.
But he warned a magnitude 5 or more quake was still possible in the next few days.
"The aftershock sequence is dying off fairly quickly. Hopefully things will start to quiet down in the next couple of days. But that magnitude 5 is still possible."
Residents took to Twitter to report this morning's aftershock, saying it shifted furniture, rocked cars from side to side and made roads seem like they were swaying.
Twitter user invervegas KDP said: "Sitting in my car for that one.. Felt like two guys were rocking it!".
gutterkitten ashley t said "That came out of no where, made me jump out of my skin".
- NZHERALD STAFF, NEWSTALK ZB, NZPA and AGENCIES