KUALA LUMPUR, Sept 22 (AFP) - Prime Minister Mahathir Mohamad may declare a state of emergency to further discredit supporters of jailed former deputy premier Anwar Ibrahim, a former veteran member of the ruling party said Tuesday.

Marina Yusof, who served four terms in the party's supreme policy-making council under both Mahathir and his predecessor, told AFP that the 71-year-old premier was a ''revengeful person'' -- as shown by Monday's arrest of the party's youth chief who tried to humiliate him at a party congress earlier this year.

Speaking in an interview at Anwar's house, Marina openly speculated about Mahathir's next move following the order to place Anwar and at least seven of his associates under indefinite detention without trial since Sunday.

''I think Dr. Mahathir may declare an emergency. He wants to create unrest and blame it on us,'' she said. ''Then he will become a complete dictator.''

Marina has openly supported Anwar since she quit the United Malays National Organisation (Umno) on September 4, the same day as he was expelled following his ouster as deputy prime minister and finance minister on September 2.

Hit by a multitide of allegations ranging from sexual impropriety to sedition, Anwar said there was a high-level conspiracy to destroy his politicial career.

He embarked a national tour and led tens of thousands in an anti-Mahathir rally in the capital on Sunday immediately before his arrest.

Marina, a 57-year-old lawyer, had earlier come to Anwar's defence, threatening to expose the dirty linen of various cabinet members if the sexual allegations continued.

She also refused to reject rumours Monday that Anwar would be injected with the HIV virus while in detention. ''To me, nothing is impossible,'' she said.

During the interview, Marina said she supported calls by Anwar's wife Aziza to keep up the fight for justice -- despite the use by police of teargas and water cannon against supporters of the former deputy prime minister.

''The situation now is tense but the reform movement must continue,'' she said.

Asked about the level of cabinet support for Mahathir amid rumours of resignations by some ministers, Marina said: ''All those who support him have got vested interests. But the moment he loses power, they will run away.''

In the meantime, she expects Mahathir's autocratic nature to prevail.

''Under Mahathir, there can be no dissent,'' she told a news conference at Anwar's house on Monday, recalling the Umno split in 1987 when then deputy premier Tengku Razaleigh challenged Mahathir for the top job.

''In 1987, I was the first to ask him to step down. I tell him again, step down. The abuse of power is blatant,'' she said.

Turning to a group of largely young Anwar supporters at the house, she advised that future protests would have to be peaceful.

''Mahathir's tactic is to plant his people and create trouble. When you all move, move in an orderly way,'' she said.

''You have to be careful. And think of the next move.''

Marina served two consecutive two-year terms as Umno supreme council member from 1972 to 1975 when Abdul Razak was prime minister. She rejoined the council in 1981 when Mahathir assumed power and served another two-year term from 1983.