Two tourism representatives speaking to RTHK on Thursday had different outlooks for tours to Japan after authorities there began discharging wastewater from the crippled Fukushima nuclear plant.

Steve Huen, executive director at EGL Tours which specialises in Japanese tours, said the impact on demand will be short-lived.

He said the number of Hong Kong people signing up for tours on Wednesday was down around 20 percent compared with each of the previous two days, but thinks the numbers will soon return to normal.

"I don't think the effects will be long-lasting. Of course everyone will observe the situation, but perhaps once they see there's no problem, they'll start travelling to Japan again," Huen said on an RTHK programme.

"I think it will take a very short time for the numbers to return to normal, I think in like two to three weeks."

Huen also said there won't be big changes to meals offered to tour groups, saying restaurants in Japan will ensure the food is safe for consumption.

The executive director of the Travel Industry Council, Fanny Yeung, is less upbeat, saying tourist figures will be down by at least 20 percent for weeks or even months.

"The food over there, especially fresh fish, is something longed for by travellers. This incident affects their confidence level and people's intention for going to Japan for holiday," she told RTHK.

Yeung said travel agencies will have to consider turning to other countries or regions, or other Japanese destinations not affected by the discharge.