Mid-winter tourism to New Zealand is booming, and more than 154,000 visitors came here last month.

The 12 per cent rise for August was helped by more emphasis being placed on promoting New Zealand's attractions in spring, autumn and winter, said Tourism New Zealand chief executive George Hickton.

A good ski season and competitive transtasman airfares had led to a growth in the number of tourists from Australia last month, up 19.4 per cent to 64,548.

Another highlight was a 20 per cent increase in visitors from the United States, Mr Hickton said.

"Advertising, billboards in key locations, involvement in the Aspen Food and Wine event, some fantastic articles ... and other media coverage which included a front cover billing in Conde Nast Traveller magazine, have combined to make New Zealand's presence felt."

August visitor numbers from Britain, Japan and China also rose by 3.6 per cent, 19.7 per cent and 48.8 per cent respectively, and numbers from Asia showed a recovery from the effects of Sars.