Tourism authorities in Heilongjiang province summoned the heads of 31 travel agencies in Harbin this week to encourage them to strengthen their management of tour guides.

The move came after the China National Tourism Administration called for a vigorous investigation into complaints of guides forcing tourists to buy ticket packages during trips to Snow Town, a popular winter attraction in the province.

The warning was issued on Monday by the Heilongjiang Tourism Development Committee, Harbin Tourism Development Committee and Heilongjiang Forest Industry Bureau.

"We will conduct a campaign to correct irregularities and promote impartiality in the winter tourism market," said Zhang Xiaochun, director of the Heilongjiang committee's supervision and administration office. "Travel agencies and tour guides that break the rules will be published on a blacklist."

It comes after video footage emerged online recently that showed tour guides asking tourists to buy ticket packages before they arrived at Snow Town.

In one recording, a male tour guide asks tourists to pay for an attraction valued at 800 yuan ($124). After a female tourist refuses, he insults her.

In addition, the guide examined the tourists' cellphones to prevent them from keeping recordings.

Tourists in the group had paid 288 yuan for the trip, which included a meal, lodging and transportation.

In another video, a female tour guide appears to pressure tourists to buy a package valued at 1,680 yuan, including several items that most tourists are not interested in purchasing.

When some tourists refuse, the guide tells them they will have to bear the extreme cold outside while the others enjoy the attractions.

The female tour guide, surnamed Shang, is a member of the Harbin Kanghua International Travel Agency, according to a preliminary investigation by the provincial committee.

"The irregularities have greatly impacted the tourism market and even the reputation of the province," said An Yuzhong, deputy general manager of Harbin Youth International Travel Agency. "The measures promoted at the meeting will greatly help standardize the market order and protect those who keep observing the regulations.

"However, it won't be easy to solve the problems immediately and it needs the joint effort of the tourism agencies and the related government departments."

He advised tourists to use qualified travel agencies and avoid choosing tour groups offering tours at unreasonably low prices. "The tour group to Snow Town, for example, can't avoid charged items if the price is lower than 600 yuan," he said.