He is ready to take measures for the development of the bank in the changing financial climate and with the participation of the people across all religions.
He spoke at a press conference at its headquarters in the capital's Dilkusha on Sunday.
"Islami Bank has a huge amount of assets. The big projects of the government will be financed through the hank, because the government never defaults. So these projects will be funded through the finance ministry though the profit will be less," he said.
A former secretary and former chairman of Bangladesh Commerce Bank, Arastoo said he is looking to make the investments on public-private partnership (PPP) arrangements.
The paid-up capital of the Islami Bank, the largest private bank in Bangladesh, is Tk 16.1 billion. Its market capital is Tk 48.29 billion.
The bank’s net profit in 2015 was Tk 3.15 billion.
Mustafa Anwar, Abdul Mannan and Azizul Haq resigned as Islami Bank chairman, managing director and vice-chairman respectively on health grounds on that day.
Ibn Sina Trust representative Mustafa Anwar, known to be a Jamaat loyalist who had been clinging to two positions – bank chairman, and Islami Bank Foundation chairman – has relinquished the positions. He no longer sits on the board as well.
Former secretary Arastoo Khan has been made chairman of the bank while another former secretary, Syed Manzoorul Islam has been appointed Islami Bank Foundation chairman.
Deputy Managing Director Mahbubul Alam is now Acting Managing Director of the bank, while Syed Ahsanul Alam Parvez filled the post of vice-chairman. Yousif Abdullah Al-Rajhi has retained the position of another vice-chairman.
At the first media call after taking charge, the new chairman said, "Countries, societies see changes. That's how the Islami Bank management has changed. But it will firmly follow Sharia laws."
Earlier in the day, Finance Minister AMA Muhith said foreign partners' ‘insistence’ was behind the changes at the top of the Islami Bank.
He thinks the bank's activities will change naturally after the changes in chairman and managing director.
Arastoo Khan said the employees of the bank are fearing for their job after the change.
"The new management will not sack anyone. Everyone will retain their job. If someone does something wrong, he or she will lose job," he added.
The Bangladesh Bank appointed an observer to the bank after allegations of funding militancy surfaced against the bank.
Muhith admitted that there were questions surrounding the use of the bank's profits, and the president of one of its sponsors, Islamic Development Bank, raised the issue with him two years ago.
Arastoo Khan said, "There might have been some irregularities in using the bank's CSR funds. The money will be spent properly from now on."
The new chairman also observed that the bank had no representation of women. He said now the bank will recruit more women and promote the existing female employees.
New Vice-Chairman Parvez said, "People had made indirect comments about the previous board. So changes to the board have been brought."