"The Bank of Japan tomorrow is the fly in the ointment," he said.
The Bank of Japan is expected to keep to its plan of stimulating the Japanese economy, which has made the yen weak.
All 23 economists in a Bloomberg News survey expect the central bank to expand asset purchases at a two-day meeting that starts today.
"Most of what they unveil tomorrow will have been priced into the yen and if anything we might get some yen buying once the news is out with people taking profit on short-yen positions," Speizer said.
"Kiwi-yen is really extremely over-bought technically and it's really screaming that it needs to correct at least a few yen," he said.
In the US, the Republican-controlled House of Representatives has signalled that it intends to support a three-month extension of the US debt ceiling.
Bancorp Treasury Services says that this would avert a government debt default in February or March.
The looming US debt ceiling fight was not yet upsetting markets, with US equities touching five-year peaks.
Speizer said a vote on this temporary debt ceiling increase on Wednesday (US time) may prove to be the most important event for the new Zealand market this week.
"The extension would put off a fight between the Republicans and Obama over a long term ceiling increase until they have negotiated two other fiscal deadlines in the next few months."
With a weaker-than-expected December- quarter New Zealand consumers price index now behind the market, the focus is turning to Australian December-quarter inflation data on Wednesday.
The headline consumers price index is expected to be softer because of weak food prices, but the core rate will be little changed.
A rate cut is expected to be discussed at the next Reserve Bank of Australia board meeting in February and a low core CPI could be a tipping point.
