MALAYSIA's Finance Minister, Datuk Seri Anwar Ibrahim, 46, was yesterday appointed Deputy Prime Minister in a promotion that puts him first in line to succeed Prime Minister Datuk Seri Dr Mahathir Mohamad. An announcement from the Prime Minister's Office said Mr Anwar would retain the finance portfolio. He succeeds Ghafar Baba, 68, who resigned in October as deputy prime minister and deputy president of the United Malays National Organisation (UMNO), the main government party. The party deputy president has traditionally become deputy prime minister. UMNO's General Assembly formally installed Mr Anwar as deputy president and acknowledged heir apparent to Dr Mahathir on November 4, but he has had to wait four weeks before taking over as Deputy Prime Minister. Analysts had speculated that Dr Mahathir delayed the appointment to demonstrate that he was still firmly in charge, following the General Assembly's endorsement not only of Mr Anwar but of a large number of his associates, known as the ''Vision Team'', which put the deputy president in virtual control of the party. The assembly elected a member of the team as UMNO Youth leader and voted in three others as vice-presidents. It also gave Anwar associates the balance of power on the policy-making Supreme Council. But Mr Anwar is not expected to make any early challenge to Dr Mahathir. A newspaper editor close to Mr Anwar said in a recent article that Dr Mahathir should continue to lead the nation until 2000. His call for the Prime Minister to remain in office for another two terms was seen as bid to reassure Dr Mahathir that he was not under threat and to close ranks within the party following the divisive campaign leading up to the elections. Mr Anwar has had a rapid rise to the upper levels of the party since he joined it in 1982. As a social activist with radical Islamic views, he was detained under the Internal Security Act in the 1970s for lobbying against the Government, but his opinions today are more moderate and pragmatic. His swift accession to power has been partly due to his ability in building up a network of allies both inside and outside the party, notably in the media. He strongly supports Dr Mahathir's plan to make Malaysia a modern, developed industrial nation by 2010 and is expected to continue with a similar progressive programme when he, as expected, eventually takes over as leader.