ISMAILIA, Egypt, Jan 31 (Reuters) - Egypt's Suez Canal Authority said on Thursday it was raising fees on shipping through the waterway by between 2 and 5 percent starting on May 1, boosting revenues for the cash-strapped government.

Tolls were raised in 2012 for all ships passing through the canal, a major source of hard currency for Egypt and vital to world trade, by 3 percent starting March 2012, saying at the time it had not raised fees in the three previous years.

The authority said this year's decision to raise tolls was taken after studies into prospects for growth in the world economy and global trade.

Egypt declared a state of emergency in three cities that lie along the Suez Canal - Port Said, Ismailia and Suez - after violent anti-government protests there. But the canal authority said the waterway was unaffected and has pledged to keep traffic running smoothly through the waterway.

Fees for tankers carrying oil, petroleum products, liquefied natural gas (LNG) and chemicals, as well as bulk carriers, would rise by 5 percent, while fees for container ships and car transporters would be 2 percent. Other ships would face a 3 percent rise in fees.

(Reporting by Yusri Mohamed; Writing by Edmund Blair and Tom Perry; Editing by Janet Lawrence)