Reports linking the pilot's political affiliation to the plane's disappearance were dismissed as wild, groundless allegations by the Malaysian opposition People's Justice Party, of which the captain is a life member.
The party said reports that captain Zaharie Ahmad Shah was at the court that sent opposition leader Anwar Ibrahim to jail on sodomy charges several hours before the pilot was to fly the plane to Beijing were untrue.
"Allegations that some tabloids in the UK have made about captain Zaharie were wild and not supported by facts," party spokesman Fahmi Fadzil said.
"I was at the trial during the two days and do not remember seeing him," he added. But he also said he did not know Zaharie was a party member until the news about the plane broke on March 8.
Fahmi said he hoped that the federal government would not use such reports to "label" opposition party members.
The Daily Mail ran a widely circulated story yesterday claiming Zaharie was a "political fanatic" and an obsessive supporter of Anwar, who was sentenced to five years' jail.
Citing unnamed colleagues, the report said that Zaharie planned to attend the court case involving Anwar on March 7 - just hours before he was to pilot flight MH370 to Beijing - and that he was reportedly there, adding that Anwar's conviction left Zaharie profoundly upset.
Investigators have so far not been able to confirm if Zaharie was in court, according to a source close to the investigation.
Sivarasa Rasiah, a member of Parliament and a lawyer representing Anwar in the case, told reporters yesterday: "He has been a party member since early last year and campaigned for us during the general election but this is irrelevant to the case.
"Even though I was not there at the trial for its entirety, I can say that he was not there. Because if he was, I would have been notified," he said.
Speculation is mounting as to who might be responsible for the disappearance of the plane. Investigations have revealed that the plane flew under the radar and that its communications systems were switched off, lending plausibility to the theory that the plane was hijacked by a person with aviation skills.
Police had intensified their checks on the two pilots, and on other crew members and passengers on the plane, Malaysian defence and acting transport minister Hishammuddin Hussein said yesterday.
Hishammuddin said that the police searched the homes of the two pilots and were looking at the captain's flight simulator.
Malaysian police chief Khalid Abu Bakar said: "Police have dismantled it and reassembled it to examine it. Meanwhile we're getting experts to look at it."
Hishammuddin said that the pilot and co-pilot did not ask to fly together, and said reports that the pilot's family had moved out a day before the flight vanished were untrue.