DUBAI (Reuters) - The United Arabic Emirates has allocated $4 billion to Egypt, half of it in investment and half as a central bank deposit to support cash reserves, the UAE state news agency WAM reported on Friday.

The report appeared to be referring to a previously announced UAE offer to give Egypt $4 billion, which was made at a conference in Sharm El-Sheikh last year along with pledges from other Gulf Arab states.

Egypt has struggled to spur economic growth since its 2011 uprising ushered in political instability that scared off tourists and foreign investors, key sources of foreign currency.

Details of the UAE aid allocation came at the end of a visit of Abu Dhabi's crown prince, Sheikh Mohammed bin Zayed al-Nahayan, to Egypt on Friday.

He said the aid, authorised by UAE President Sheikh Khalifa bin Zayed al-Nahayan, showed the UAE was firm in its support for Egypt.

The money was aimed at promoting development in Egypt, which has a "pivotal role" in the region, WAM quoted Sheikh Mohammed as saying.

Earlier this month Egypt and Saudi Arabia signed a pact to set up a 60 billion Saudi riyal ($16 billion) investment fund.

At the Sharm El-Sheikh conference in March 2015, Kuwait and Saudi Arabia each also offered $4 billion to Egypt.

($1 = 3.7499 riyals)

(Reporting by Sylvia Westall and Omar Fahmy)