Private homes and hospital beds could be used to host hundreds of supporters when the Lions play Otago in Dunedin.

About 80 per cent of the city's more than 2500 guest beds are already booked in the lead-up to the June 18 game, leaving tourism bosses pondering the use of "overflow" accommodation to meet demand.

Dunedin will consider using private homes and rooms at Wakari Hospital, Tourism Dunedin marketing manager Ryan Craig said.

"We haven't had to turn to either of those options yet, like we have for the Bledisloe Cup, because the New Zealand Rugby Union ticket ballot is still going and we won't know what the final demand will be for a while yet," Mr Craig said.

"We are familiar with providing overflow accommodation, and can do it again if we have to."

The union has said 3000 Lions fans have bought package deals to visit the city, and another 500 to 1000 tourists would likely arrive without tickets "to soak up the atmosphere".

The same number were expected to visit Invercargill for the Southland game three days later.

A tourist "explosion" of up to 15,000 fans is expected for the first test against the All Blacks in Christchurch on June 25.