The World Bank's outlook was significantly below the central bank's forecast of 7.53 percent last month, and a 6.4 percent estimate from nine analysts polled by Reuters in January.
Sub-Saharan Africa's second biggest economy, once a darling of frontier market investors, hopes its fortunes improve as the global economy gradually recovers, and after fixing problems in its banking sector rescued in 2009 by the regulator.
"This economy is just waiting for a bedrock of right and consistent policies ... to get some of our sectors going," said Ngozi Okonjo-Iweala, the World Bank's managing director for Africa, at an economic conference in Lagos.
To improve the OPEC member's economy in the long run, she said Nigeria's leadership must find a way to solve the country's unemployment problem, especially among its young.
She estimated unemployment for 15-24 year olds at around 31 percent..
Africa's most populous country of 140 million people will need to create 24 million jobs over the next decade to cut unemployment by half, Okonjo-Iweala said.
"The most worrying is that an estimated 50-60 percent of our graduates from tertiary institutions cannot find an adequate job on completion of studies," she said.
The vast majority of Nigerians live on less than $2 a day, despite having Africa's biggest oil and gas industry.
Widespread poverty has led to the growth of militant groups in the oil-producing Niger Delta in recent years, and has helped stoke sectarian tensions in the country's "Middle Belt."
