Khaled Mashaal said on Thursday that he hoped that funds would not be withdrawn, but said that Hamas will maintain its belief in armed resistance and will not recognise Israel.
"Hamas can never trade its principles for money," Khaled Mashaal said. He was referring to US and EU demands that it accept Israel and commit itself to peace if it seeks to maintain the flow of Western aid to the Palestinian Authority after it has formed a government.
Mashaal was speaking in Qatar while on a tour of Arab states designed to shore up support for his movement. Earlier this week he was in Egypt.
Hamas, which won a landslide victory in last month's elections for the Palestinian legislature, is expected to form a government in the coming weeks.
Each year the authority receives about $900 million from Western donors, particularly the United States and EU, which have said that they will not fund an entity that sees Israel as an illegitimate state founded on a Palestinian Arab Muslim land.
Mashaal told reporters: "It is in the best interest of America and the West to deal with a victorious group, a group that the people are rallying behind."
"We are capable of finding alternatives" to Western aid, he said. These include saving money by eliminating corruption within the authority and receiving aid from Arab countries, which have made "good promises and commitments".
Hamas is listed by the United States as a terrorist group. Referring to this, Mashaal said: "Washington is not punishing Hamas, but it is punishing the Palestinian people."
Mashaal defended the group's refusal to recognise Israel by saying: "We are not proposing throwing Israel in the sea. But we want to regain the [Palestinian] rights and to end the occupation."