RAMALLAH, West Bank, June 14 (Reuters) - President Mahmoud Abbas has said any new system for supplying the Gaza Strip must involve his West Bank-based government -- a position rejected by the Hamas Islamists who govern the territory. The Western-backed Palestinian Authority's demand for a role in managing supplies to Gaza, blockaded by Israel, collides with Hamas's aim of harnessing pressure over the embargo to win the international recognition it has sought.

Our government is the legitimate representative of the Palestinians in the West Bank and the Gaza Strip, Abbas said in an interview with al-Ayyam newspaper published on Monday.

Therefore, any steps or measures from the Israeli side or the international community must come via this government.

Middle East envoy Tony Blair said on Monday he expected Israel to begin easing the blockade within days.

In an interview with the BBC aired on Sunday, Blair spoke of a potential role for the Palestinian Authority, for the European Union, and of course for the United Nations itself in supervising a new system. Hamas defeated Abbas's Fatah faction in 2006 legislative elections and views Abbas as an illegitimate president who conspired to undermine the group following the vote.

Hostile to Israel, Hamas took control of Gaza from Abbas's forces in 2007, prompting Israel to tighten supply restrictions on the territory. Israel now faces international pressure, including from the United States and the European Union, to lift or loosen the blockade, which it says stops Hamas from arming.

PRESSURE

Salam Fayyad, prime minister of Abbas's administration, in an interview with Reuters last week called for the activation of a 2005 agreement on access to Gaza that would restore a role for PA forces in managing crossings.

Fayyad's administration receives political and financial backing from Western states. Hamas, by contrast, is shunned because of its rejection of Israel's right to exist and its refusal to renounce violence and sign up to interim peace agreements between the PA and Israel.

Hamas has been emboldened by pressure on Israel to ease the blockade, which increased after a lethal Israeli naval raid on a Turkish aid ship trying to break the embargo.

Hamas spokesman Sami Abu Zuhri said the 2005 agreement had expired and Abbas's administration could have no role in managing supplies to Gaza.

(Abbas) does not exist in Gaza and therefore any international intervention, especially by the Europeans, must come through the government in Gaza, he said. (Reporting by Tom Perry and Nidal al-Mughrabi; writing by Tom Perry; editing by Peter Graff)