But both insisted they had done nothing wrong and brushed off mounting calls for an apology and their resignation, as well as threats of legal action against them.

Watch: three Hong Kong lawmakers have oaths rejected

“In the oath, it doesn’t mention any specific person ... I don’t know how we could have offended anyone,” Leung said.

At the inaugural Legco meeting last Wednesday, the pair pledged allegiance to “the Hong Kong nation”, referring to the sovereign state as “Chee-na”, a variation of the derogatory “Shina” used by Japan for China during the second world war.

They also displayed a banner with the slogan “Hong Kong is not China” while they were being sworn in.

Their oaths were invalidated by Legco secretary general Kenneth Chen Wei-on.

Mok Ka-kit, a student at City University, applied for a judicial review in the High Court on Monday over the legality of the oaths taken by the Youngspiration pair.

Mok asked the court to disqualify Yau and Leung on the basis of unconstitutional oaths taken under the Oaths and Declarations Ordinance.

According to the law, Legco members are required to swear allegiance to the Special Administrative Region of Hong Kong, and refusal to take the oath properly could lead to disqualification .

In a separate judicial review application filed on Friday, solicitor Dr Siu See-kong, who failed to win a Legco seat in several past attempts, argued that Yau had lost her right to sit in the chamber as a Chinese national by advocating independence for the city.

Siu asked the court to seek an interpretation from the national legislature of the requirement to be a “Chinese national” to run in Legco elections.

Apart from Yau, the Electoral Affairs Commission was named a co-defendant in the case. Leung was not.

Eric Cheung Tat-ming, a legal scholar at the University of Hong Kong, said the court challenges were mere political gestures and did not have strong legal grounds.

“They haven’t failed to take their oaths so far,” he said.

Over a dozen adverts appeared in local newspapers on Monday, slamming the Youngspiration pair and demanding they apologise and quit.

While Leung maintained his pronunciation of “China” as “Chee-na” was due to his “Ap Lei Chau accent”, a group of residents from the island rejected his excuse.

“Leung Chung-hang’s terrible action has made those of us who were born and bred in Ap Lei Chau angry,” they said in a joint statement.

Leung and Yau are set to retake their oaths .on Wednesday in front of new Legco president Andrew Leung Kwan-yuen, along with architecture representative Edward Yiu Chung-yim, whose oath was also invalidated.

The Legco president replied that he would announce his decision on the matter on Tuesday.