The 94-page "phase one" trade deal left in place existing US tariffs on US$370 billion ($557.7b) of Chinese imports and Chinese tariffs on US$120b of goods from the US until a phase two deal has been reached.
"That took a lot of the initial hurrah out over phase one," said Martin Rudings, an adviser at OMF.
Ahead of the signing, investors had been unwinding long kiwi positions against the Australian dollar in anticipation that the deal would boost the Aussie currency.
"People are putting those long kiwi positions back on because the problem hasn't gone away. They've just kicked the can down the road," Rudings said.
Another factor favouring the kiwi over the Aussie is that National Australia Bank's economists have predicted the Reserve Bank of Australia will cut its cash rate twice this year – most analysts and market pricing has been suggesting just a single rate cut.
RBA next meets on February 4 after cutting the cash rate from 1.5 per cent to 0.75 per cent last year.
NAB expects the RBA will cut 25 basis points in the current quarter and another 25 points in the June quarter, taking the cash rate to 0.25 per cent.
While New Zealand's Reserve Bank cut its official cash rate from 1.75 per cent to 1 per cent last year, the chances of further cuts this year are looking increasingly unlikely.
Data released today showed that while electronic card spending dipped 0.8 per cent in December, that was after a 2.9 per cent lift in November and economists said retail spending momentum remains strong.
And the housing market continued its recent revival with house price inflation continuing to accelerate in December as prices hit fresh records both nationally and in all but two out of 12 districts.
In addition, sales volumes were at their highest level for a December month in three years, despite a further tightening of supply, according to the latest figures from the Real Estate Institute of New Zealand.
NAB expects RBNZ will hold the OCR steady and that therefore the differential between NZ and Australian interest rates will widen.
The New Zealand dollar was trading at 50.82 British pence from 50.72 yesterday, at 59.45 euro cents from 59.36, at 72.88 yen from 72.60 and at 4.5642 Chinese yuan from 4.5560.
The two-year swap rate rose to a bid price of 1.1949 per cent from 1.1790, while 10-year swaps nudged up to 1.6450 per cent from 1.6425.