UPDATE 1-U.S. policy on Iran won't harm its oil sector - minister

* Iran plans to boost oil, gas output by 2021

* To sign 10 new oilfield deals by March 2018 (Adds details, quotes, background)

LONDON, Oct 17 (Reuters) - U.S. President Donald Trump's revised hardline policy towards Iran will have little impact on Tehran's ambition to develop its vital oil sector and attract foreign investment, a senior Iranian official said on Tuesday.

The Islamic Republic hopes to signs 10 new deals with foreign companies to develop new oil and gas fields by March 2018, Amir Zamaninia, Iran's deputy oil minister for trade and international affairs, told the Oil & Money conference in London.

Trump's decision last Friday not to certify that Iran was complying with a landmark 2016 international nuclear deal will not detract from Tehran's plans, he said.

"I don't think any of us, or any of our partners have been surprised by this statement. Our expectations of policy formulation from Washington have been very measured," he said.

"The (U.S.) statement and policy ... has little or no effect and implication on our future plan in the oil industry," Zamaninia said.

Iran is negotiating 28 contracts with foreign companies, including many of Europe's top oil companies, under a new development contract, he added.

France's Total became in July the first western oil major to re-enter Iran following the lifting of international sanctions with an agreement to develop the giant South Pars offshore gas field.

Royal Dutch Shell has also signed an agreement with Iran for the possible development of oil and gas fields.

Iran, which holds the world's largest gas reserves, plans to boost its gas production to 1.1 billion cubic metres per day by 2021 from the current 800 million bcm per day, he said.

The OPEC member also aims to raise its oil production capacity to 4.7 million barrels per day by 2021 from the current 3.8 million bpd, he said.

He said that the major oilfields - Azadegan, Yadavaran, Abteymour and Mansouri - have potential to increase output by 2 million bpd combined. (Reporting by Ron Bousso and Julia Payne; Editing by Adrian Croft)