Anwar, who was released from prison two months ago, spoke to about 1000 supporters gathered at his house to welcome him from a trip abroad.
"Don't think that just because Anwar Ibrahim is free, everything is settled," he said.
"The release of Anwar is the beginning of a new chapter. In this chapter we must defend the fate of all people in Malaysia and ensure that our leaders are not arrogant and greedy," the former deputy prime minister said.
However, Anwar promised not to take to the streets as he did in 1998 after falling out with then Prime Minister Mahathir Mohamad, his former mentor and longtime colleague in the ruling United Malays National Organisation party.
Anwar was subsequently arrested, tried and sentenced to 15 years in jail on sodomy and corruption charges.
The sodomy charge was overturned by a court and he was freed from jail on 2 September as he had already served his corruption conviction. He went to Germany on 4 September for back surgery and subsequently to Saudi Arabia on pilgrimage.
The corruption conviction means he cannot hold a public post until 2008.
Anwar's wife, Azizah Ismail, started the opposition People's Justice Party when he was in jail.
The former deputy PM said he
would discuss a new approach
About 1000 supporters, including members of the party, evaded a massive police cordon to greet him at the airport on his arrival from Jedda, Saudi Arabia, and another 1000 awaited him at his home in a Kuala Lumpur suburb.
Anwar told them he would seek out a meeting with Mahathir's successor, Prime Minister Abdullah Ahmed Badawi, who completed one year in office on Sunday.
The meeting would be to discuss "a new approach in Malaysian politics with the agenda of change and reform", Anwar said, taking a conciliatory approach towards his former colleagues turned political foes.
"Our struggle remains, our fight remains. My agenda is to bring change and reform," said Anwar. He praised Abdullah for initiating several democratic changes such as less interference in the judiciary and the press, but stressed that "our problems remain plenty".
"We want to create a Malaysia that truly stands for justice and goes beyond the interests of just one race or party. We will need the support of everyone," Anwar said.
"Our struggle remains, our fight remains. My agenda is to bring change and reform"
He said his main concerns were the large gap between the rich and the poor, race relations between the Malay, Chinese and Indian communities of Malaysia, and corruption. He made it clear that he has no intention of joining UMNO.
"When I say that I want to meet the prime minister there, seem to be many worried faces thinking that I want to rejoin UMNO but I have never said that," Anwar said.