In fact, National had tightened overseas investment rules and less farmland had been sold to foreigners than under the previous Labour government, he said.

Mr Key was responding to poll results that showed his personal popularity and National's numbers down slightly.

The 3 New Reid Research poll also showed 76 per cent agreed rules should be changes to make to tougher for land to be sold to foreigners.

Among National Party supporters, 68.7 per cent agreed the rules should be tougher. Of Labour voters, 81.2 per cent agreed; of Green voters 82 per cent agreed and 95.7 per cent of New Zealand First supporters agreed.

Less sales had occurred under National with just 72 farms sold to foreigner owners in the last 18 months, Mr Key told TV3's Firstline programme.

"There's a bit of perspective there. It's not a run on farms, it's just that Crafar is very high profile."

National was aware of the sentiment around sale of land to foreigners and that was why it had tightened the rules, he said.

"New Zealanders do feel very strongly about foreigners coming and buying land in New Zealand. That's not a new issue and I think that's been a widely held view.

"Actually, by a number of studies, New Zealand is quite a difficult place to buy land if you're a foreigner."

Key said a ruling by Justice Miller on the controversial sale of the Crafar Farms to the Shanghai Pengxin conglomerate may have already had the effect of tightening the law.

The ruling by Justice Miller late last week sent back an approval of the Shanghai Pengxin bid for the farms for re-consideration by the Overseas Investment Office (OIO). Justice Miller found the test for economic benefits had not been properly applied by the OIO.

The Government was still considering whether to appeal the decision and a possible law change in response to

it.