Oracle Corp on Thursday forecast current-quarter cloud revenue growth that missed Street expectations after reporting disappointing second-quarter sales in the same business, sending its shares down nearly 7 per cent after hours.

The company has seen its shares rise nearly 30 per cent this year as investors bet that its efforts to switch to the cloud would pay off.

Oracle said growth in its cloud-computing business would slow to 21 per cent to 25 per cent in the third quarter, down from the 44 per cent growth in the preceding quarter. The forecast was also below analysts' estimates.

The company's current-quarter profit expectations also came in below analysts' estimates.

Oracle, which inked cloud deals with AT&T and Bank of America this year, is a late entrant to the cloud-based business and has been stepping up efforts to catch up with rivals such as Amazon.com, Microsoft and Salesforce.com.

"Oracle has largely made the transition on SaaS but still have a lot of work ahead on transitioning the database business to the cloud," said Wedbush analyst Steve Koenig.

In October, the company launched its machine learning-based autonomous database cloud to better compete against market leader Amazon Web Services (AWS).

"Investors were expecting more...Microsoft and Amazon are in a two-horse race that is well above any other competitor and everyone else is chasing them, including Oracle," said Daniel Ives of research firm GBH Insights.

Amazon posted a 42 per cent rise in cloud sales to US$4.58 billion in the quarter to September, while revenue in Microsoft's Azure services surged 90 per cent during the same period.

Oracle forecast current-quarter adjusted profit between 68 cents US and 70 cents US per share, compared with analysts' expectations of 72 cents US, according to Thomson Reuters I/B/E/S.

Oracle, which increased its share buyback program by US$12 billion, said net income rose to US$2.23 billion, or 52 cents US per share, in the second quarter ended Nov. 30, from US$2.03 billion, or 48 cents US per share, a year earlier.

Total adjusted revenue rose 6.2 per cent to US$9.63 billion, beating expectations of US$9.57 billion, according to Thomson Reuters I/B/E/S.

Revenue in Oracle's traditional software licensing business, by far still its largest, rose three per cent to US$6.31 billion.

On an adjusted basis, Oracle earned 70 cents US per share, topping analysts' estimate of a profit of 68 cents US.