WARSAW, Jan 17 (Reuters) - Poland is likely to have had more victims of phone hacking using spyware developed by Israel-based NSO Group, a researcher told a commission, after allegations that Polish special services used the technology against government opponents. Canadian researchers said late last year that phones of a senior opposition politician and two prominent government critics were hacked using Pegasus software. The findings were first reported by the Associated Press. John Scott-Railton, a senior researcher at the University of Toronto"s Citizen Lab project, told a Polish Senate commission on Monday he had seen evidence of other hacking and that he expected there to be other victims. Jaroslaw Kaczynski, the leader of Poland"s ruling nationalist Law and Justice (PiS), said this month that the country had access to Pegasus, but said suggestions it was used against political opponents were "utter nonsense". read more Poland"s opposition-controlled upper house of parliament, the Senate, created the commission to look into the allegations of phone hacking, but it has no official investigative powers. The PiS-controlled lower house of parliament has resisted calls for a full investigative commission. No PiS senators took part in the commission on Monday. A spokesman said the government did not see the need for any further investigative proceedings as surveillance was only possible with the agreement of a court, adding that if someone thought the law had been broken they could take legal action. Citizen Lab says the phone of Senator Krzysztof Brejza was broken into 33 times in 2019 and data taken from it. At the time, Brejza was running the election campaign of the largest opposition party, Civic Platform. Other victims Citizen Lab has identified are prosecutor Ewa Wrzosek, a critic of the government"s judicial reforms, and Roman Giertych, a lawyer who has represented opposition figures.