ISLAMABAD, Feb 8 (Reuters) - Pakistan is set to sign a 15-year import deal for 3.5 million tonnes of liquefied natural gas (LNG) per year from Qatar, a Pakistan government official said on Monday.

Previously the two governments had discussed a 15-year deal for 1.5 million tonnes per year with scope for the volume to increase over time.

The official said details of the terms would be announced ha later this week, adding that Pakistan had secured the LNG at a competitive price.

"Due to the drop in oil prices, we were able to secure a very viable deal. It has been a very favourable deal to Pakistan," the official said, adding that the deal's first volumes could be delivered as early as March or April.

Pakistan, along with Egypt and Jordan, were newcomers to the LNG import market in 2015, helping drive up demand and absorb growing world supplies from a wave of new projects.

Pakistan's first floating import terminal (FSRU) received its initial spot imports in April last year and has import capacity for around 4.4 million tonnes of LNG per year. The country has also tendered for a second FSRU planned to be operational by mid 2017.

The nation of 190 million people can only supply about two-thirds of its gas needs. The ruling party, which campaigned on promises of solving the energy crisis, wants to ease shortages by expanding LNG shipments before a 2018 general election.

Last month Pakistan State Oil backed out of a nearly $1 billion deal to buy LNG from Royal Dutch Shell after receiving a lower price from Qatar, sources said.

(Reporting by Krista Mahr, writing by Sarah McFarlane, editing by Louise Heavens) ((sarah.mcfarlane@thomsonreuters.com; +44 20 7542 5937; Reuters Messaging: sarah.mcfarlane.thomsonreuters.com@reuters.net))