Yesterday Mr English said he understood some work was already underway amongst New Zealand officials on the issue.
Mr Key, on the other hand, said he wasn't aware of any work being done.
"According to the advice I've had this afternoon Land Information might be looking at the broader issue but as far as I'm aware they're not working on a register and I've always said and maintained, we could always introduce a register but the real issue here is building new houses."
Mr Key said it was "possible" a register could be established during this parliamentary term. "It's not something we've absolutely ruled out we just don't think that that takes you a long way."
Land Information Minister Louise Upston said she didn't have details on the work being done by officials in her own department.
"There's been a number of questions I've asked over the last couple of months so they've just been doing some preliminary work to see where it goes."
However, Ms Upston said she was unsure whether officials were working on the general issue of information about foreign buyers or specifically about a register.
A spokesman for Land Information NZ yesterday confirmed the department had "done some preliminary work to look at what might be involved if the government were to consider implementing a register of foreign ownership of land".
"We will continue to monitor developments around the world in terms of land and property registers." However Land Information NZ was working on a general register of land ownership rather than one specifically focussed on residential property.
The department, which includes the OIO, also said it had recently received an application from a company associated with Shanghai Pengxin "to acquire a commercial property in central Auckland".
"However all details in relation to that application are confidential at this time."
Overseas buyers must seek OIO approval for purchases of sensitive land or assets worth more than $100 million.
Pengxin International chief executive Gary Romano said he was not familiar with the proposed purchase but it was separate from the company's purchase of the Gulf Harbour development on the Whangaparaoa Peninsula north of Auckland.
Shanghai Pengxin recently purchased the Hilton Hotel in Queenstown and already owns the former Crafar dairy farming portfolio as well as Gulf Harbour.
Mr Romano said his company would have no concerns about a register of foreign land ownership.
"We'd be more than happy to comply with whatever the requirements actually are. We'd have no objections at all."
Labour's housing spokesman Phil Twyford said news of officials' work on the register came as a surprise yesterday.
"It wasn't very long ago that the Government was saying it was racist or xenophobic to even propose such a thing, now we find out they've actually been developing a register for foreign buyers.
"It's just another example of the Government not being upfront with New Zealanders.
"Clearly this register was a policy they were planning to launch as a big start to next year. Too bad their secret register has been discovered."
A register of foreign land ownership:
• Land Information NZ says it has done some preliminary work to look at what might be involved if the government were to consider implementing a register of foreign ownership of land.
• Land Information NZ's work has been around a register of foreign ownership of land in general rather than just residential property.
• Prime Minister John Key won't rule out a register being put in place within the next three years.
