" … These are an educated man's dirty tricks. It's a higher level of trickery. As long as we have this kind of opposition, Singapore opposition politics will always be at that low level," he added.
Every word in the statement made by Home Affairs Minister Wong Kan Seng is "justified and can be defended in any court", said Mr Lee.
"So we say Gomez is a liar and dishonest. He can say its libel. He can sue Wong Kan Seng. He can sue me. But he's got to go to the witness box," said Mr Lee.CNA
Defending and winning a position which is contrary to the whim of the PAP is unheard of in a Singaporean court.
Singapore (dpa) - Singapore's founding father Lee Kuan Yew called an opposition candidate a "liar" and accused him of stage-managing an incident involving an election form, but on Wednesday James Gomez was still in this week's general election race.
Acknowledging he was aware he had become "the candidate under fire," the Workers' Party (WP) candidate said he was focused on fighting for a parliamentary seat in the body dominated by the ruling People's Action Party (PAP).
In his first rally speech ahead of Saturday's polls, Minister Mentor Lee accused the ethnic Indian Gomez on Tuesday night of trying to damage the Singapore government and the Elections Department by falsely making it seem as if he had been deprived of a minority candidate certificate when he claimed to have filed a form when in fact he had not.
Turning to Workers' Party chief Low Thia Khiang, who has stood by Gomez and vouched for the sincerity of the candidate's weekend apology to the department, Lee said Low is "still trying to cover up, shield James Gomez."
PAP leaders, including Lee, called for the 41-year-old researcher to withdraw noting the government's evidence proved his "blatant dishonesty."
Gomez said on April 26 that he had submitted his minority race candidacy form to the department and threatened consequences if it was not found, but a security camera recording showed that Gomez had put the document back in his briefcase while at the department.
Supporters have launched an online petition drive to keep him in the race.
Analysts said the issue is theatening to hijack the hustings.
"I don't think if it drags on, it will do either party any benefit," said Eugene Tan, an assistant law professor at Singapore Management University.
"In the end the voters will probably stand to lose because the real issues that matter from the PAP and opposition's perspective don't get aired."
Lee's remarks followed the release of an 11-page statement by Deputy Prime Minister Wong Kan Seng on the saga. Putting together data from closed-circuit television footage, taped phone calls at the department and a conversation between Gomez and PAP candidate Inderjit Singh, Wong said there had clearly been blatant dishonesty on Gomez's part.
Gomez said at another rally that he expected to remain the target of the PAP and predicted the attacks would intensify.
He urged voters to use calls or cellphone messages to tell others to keep focused on the election, regardless of PAP efforts to break down the opposition.
Low, one of the two opposition legislators in the 84-seat parliament, said it was more important to focus on election issues. "The party has moved on," he said.
Singapore requires parties to assemble ethnically balanced tickets, including Malays, Indians and other minorities in the predominately Chinese city-state.
The WP, Singapore Democratic Alliance and other opposition parties are trying to thwart the PAP's aim of a clean slate in parliament. The opposition managed to stop the PAP from catapulting back into power on Nomination Day for the first time in 18 years, with other parties fielding candidates in 47 of the 84 seats.
Lee Hsien Loong, in his first election since becoming premier in August 2004 after Goh Chok Tong stepped down, dispatched the senior minister to the two opposition wards in hopes of swinging voters to the PAP and removing Low and and Chiam See Tong.
Low, 54, has been in parliament for 15 years, and Chiam, 71, for 22 years.