The Organization of Petroleum Exporting Countries (OPEC) is very positive on demand for oil in both the short and long term, Secretary General Haitham Al Ghais said at an energy industry event in Abu Dhabi on Monday.

"There are some challenges, but the picture is not as negative as some make it sound," he said, adding that so-called peak demand would not happen while the global economy continues to grow.

Ghais said the oil producer group was upbeat on the global economy, noting growth in the U.S. and in China, adding that 5% growth is still very good for a country of China's size, even if it achieved up to 10% in previous years.

He also reiterated his view that demand will not peak any time soon.

"It reminds me of all the talk on peak supply many years ago. Peak supply never happened and peak demand won't happen as the world keeps growing," he said.

OPEC expects demand to keep growing for a longer period than forecast by the likes of the International Energy Agency, which expects oil use to peak this decade.

OPEC and its allies, known collectively as OPEC+, have been cutting supply to support the market.

Ghais was speaking a day after the group said it had agreed to delay a planned December increase to oil output by one month, citing downward pressure on the oil market from weak demand and rising supply outside the group.

Oil prices rose by about 3% on Monday.

(Reporting by Yousef Saba, Alexander Cornwell and Nadine Awadalla Writing by Maha El Dahan Editing by Louise Heavens and David Goodman)