Egypt has already received billions of dollars in aid from Saudi Arabia since the overthrow of former president Mohamed Morsi
Saudi Arabia has pledged a total of eight billion dollars in investment and aid to Egypt over the next five years, as Riyadh looks to boost military and economic ties with its ally.
The announcement was made during a visit to Cairo by Saudi Arabia’s Deputy Crown Prince and Defence Minister Mohammed bin Salman on Tuesday.
Saudi's King Salman "ordered that Saudi investments in Egypt exceed 30 billion riyals ($8 billion)" and that the kingdom "contribute in providing Egypt with its needs for petrol," said a statement published by the Saudi Press Agency.
In addition, Saudi ships would "support" traffic in the Suez Canal.
The pledges come despite a sharp fall in Saudi Arabia's income from oil, which makes up over 90 percent of public revenues, due to the global decline in crude prices since June last year.
OPEC kingpin Saudi Arabia has offered billions of dollars in aid to Egypt since the 2013 military overthrow of president Mohamed Morsi in a popularly backed coup against his Muslim Brotherhood government.
In November, the two countries agreed to establish a coordination council tasked with implementing the “Cairo Declaration,” which outlines facets of cooperation between the two states.
In March, Saudi Arabia, Kuwait and the United Arab Emirates each offered $4 billion in investment and aid.
Egypt is taking part in a Saudi-led coalition that has been battling Shia Houthi rebels in Yemen since March.
It is also participating in a 34-member alliance to fight "terrorism", which was announced on Tuesday by Prince Mohammed.
During his visit, Sunni Islam's leading seat of learning, Al-Azhar, urged all Muslim countries to join the new coalition.
Cairo is fighting a swelling insurgency led by the Islamic State group in the Sinai Peninsula.
But it has been criticised by rights group for carrying out a crackdown on Morsi's Muslim Brotherhood that left hundreds dead and tens of thousands imprisoned.