KPO councillor Elke Kahr said in a statement that they had passed the 10,000 signatures needed for a referendum to take place.

The KPO are considered among the main opponents to Graz, which replaced Innbsruck as the Austrian candidate for the 2026 Games after a referendum was lost there, bidding for the event.

Figures involved in the bid have pointed out that laws in Graz and Styria appear to stipulate that referendum results are not binding, however.

"We already have more than 10,000 signatures, but continue to collect and will submit the signatures in the summer months," said Kahr.

"Then it's up to Mayor Siegfried Nagl to ask people before the decision is made.

"Graz citizens must have the right to participate in such a far-reaching and momentous decision for their city."

According to reports in the Austrian media, the KPO claimed the results of a feasibility study conducted into Graz's bid raised more questions than answers.

The study claimed Graz's 2026 Winter Olympic plans were "absolutely feasible" and that a Games in the region is "possible without great risk".

A reliance on existing sporting infrastructure and local sporting expertise would supposedly mean that "cost explosions as in Games in the past could be excluded from the beginning".

The proposed €1.137 billion (£1 billion/$1.3 billion) budget would be dependent on no public money, the study concluded, while a domestic revenue projection of €1.67 billion (£1.48 billion/$1.93 billion) was forecast.

Public money would be required for security and possible infrastructure projects related to the Games, however.

A similarly positive study about a sustainable Olympic bid from Innsbruck did not prevent the bid suffering a crushing defeat in October when its referendum was held. 

A total of 53.35 per cent of those who voted rejected the idea in the public ballot in the Tyrol city in October.

Calgary in Canada, Sapporo in Japan, Erzurum in Turkey, Stockholm in Sweden and either Milan, Turin or Cortina d'Ampezzo in Italy are other cities still bidding for the 2026 Games.

Calgary could face a referendum at the end of this year while a bid from Sion in Switzerland was scuppered earlier this month after a failed vote.

A final decision on who will host the Games is due to be made by the International Olympic Committee next year.