They are among several governments accused of monitoring activities of dissidents and other critics
Saudi Arabia and the United Arab Emirates have dismissed allegations they used Israeli-supplied Pegasus malware to spy on journalists and human rights activists.
A statement by the UAE's foreign ministry on Thursday said "allegations ... claiming that the UAE is amongst a number of countries accused of alleged surveillance targeting journalists and individuals have no evidentiary basis".
Such allegations "are categorically false", it added.
Saudi Arabia's official SPA news agency reported late Wednesday that "a Saudi official denied the recent allegations reported in media outlets that an entity in the Kingdom of Saudi Arabia used software to monitor phone calls".
"The source added that such allegations are untrue, and that KSA's policies do not condone such practices."
The UAE normalised its relations with Israel in a US-brokered deal last year, but regional heavyweight Saudi Arabia still has no formal ties with the Jewish state.
Saudi Arabia and the UAE are among several governments around the world accused of using Pegasus spyware to monitor the activities of dissidents and other critics, following the leaking of a list of 50,000 alleged potential surveillance targets to rights groups.
Those groups, Amnesty International and Paris-based Forbidden Stories, collaborated with a clutch of media companies, including the Washington Post, the Guardian and France's Le Monde to analyse and publicise the list.
Israel's NSO Group and its Pegasus malware -- capable of switching on a phone's camera or microphone and harvesting its data -- have been in the headlines since 2016, when researchers accused it of helping spy on a dissident in the UAE.
A giant of Israeli tech with 850 employees, NSO insists its software is only intended for use in fighting terrorism and other crimes, and that any other use is the work of "rogue" operators.
Those claims are rubbished by human rights group Amnesty International.
"NSO's spyware is a weapon of choice for repressive governments seeking to silence journalists, attack activists and crush dissent, placing countless lives in peril," Amnesty chief Agnes Callamard said in a statement.