Egypt's finances, in havoc from political strife since Egypt's 2011 popular uprising, worsened in the first five months of 2013, with the budget deficit widening to almost half of all state spending.
Foreign reserves fell to $14.9 billion in June, representing less than the three months of imports that the International Monetary Fund considers to be a minimum safe cushion. Only about half of the reserves are in the form of cash or in securities that can be spent easily.
The mounting distress pushed Mursi to approve a 24.2 percent increase in borrowing to finance the budget deficit days before he was deposed, a law published in the official gazette on Sunday showed.
Central bank governor Hisham Ramez told Reuters the Saudi funds arrived in the form of a five-year interest-free deposit at the bank.
The bank had already received $3 billion from the United Arab Emirates on Thursday, $2 billion of which was a cash deposit and $1 billion an outright grant.
Kuwait has pledged $4 billion and Saudi Arabia a further $2 billion in energy products and $1 billion in cash. Ramez said no date had been set for the Kuwaiti payment and did not indicate when the Saudi $1 billion is expected.
The law signed by Mursi increased total government spending on energy subsidies by 20 billion Egyptian pounds and boosted interest payments on government debt by 12.65 billion pounds.
Foreign buyers largely fled Egyptian securities after the uprising that toppled Hosni Mubarak in early 2011, forcing the government to rely on local banks for finance. Interest rates were pushed into double digits.