By Phuong Nguyen and Francesco Guarascio

HANOI, March 13 (Reuters) - Vietnam's aviation regulator has proposed to recognise China's aircraft design certifications as equivalent to U.S. standards, facilitating the entry of jets from Chinese state-owned planemaker COMAC, according to documents seen by Reuters.

COMAC has been intensifying its efforts to gain a market presence in Vietnam following meetings with the country's top leaders and enticing offers to its leading budget airline as part of a wider push to attract global buyers for its domestically-produced jets.

But Vietnam is also attempting to reduce its trade surplus with the U.S. after President Donald Trump's announcement of reciprocal tariffs by confirming its intent to buy Boeing BA.N 737 MAX jets.

"New aircraft like COMAC that are not yet certified by the FAA or EASA will encounter problems with current legal regulations when seeking to operate in Vietnam," according to a Civil Aviation Authority of Vietnam (CAAV) document that referred to the U.S. and European aviation regulators.

The CAAV has proposed to change the rules to allow for the import of Chinese-certified planes effective on April 30, according to a second document, though that would require a sign-off from Vietnam's top leaders.

The CAAV, the prime minister's office and the construction ministry, which also covers transportation, did not immediately respond to requests for comment.

The proposed amendment, which would pave the way for COMAC aircraft to fly in Vietnam, aims to provide Vietnamese airlines with more options, as they currently rely heavily on Boeing BA.N and Airbus AIR.PA models.

Reuters reported in January that VietJet VJC.HM, Vietnam's leading private airline, was considering a short-term lease of two COMAC C909 regional jets for a domestic route. The arrival of the planes, initially scheduled for mid-January, has been delayed due to regulatory approval issues.

Two C909 planes previously in Chengdu Airlines' fleet have been listed under VietJet's fleet since late January, marked with vietjet.com logos and the number 75 to signify 75 years of Vietnam-China relations, according to registration information on FlightRadar24 and photos on plane-spotting websites.

One of these made a demonstration flight to Vietnam on January 23, stopping in Hanoi, Ho Chi Minh, Con Dao and Hanoi again before returning to Chengdu.

VietJet did not respond immediately to requests for comment.

Vietnam and China, which have deep economic ties, have recently embarked on cooperation in sectors such as defence and transport infrastructure.

But Vietnam also has major trade relations with the U.S., where the Southeast Asian nation's trade and industry minister is traveling this week in a bid to avoid tariffs. Officials have repeatedly cited purchases of U.S. planes as a way to reduce Vietnam's large trade surplus with the U.S.

VietJet has 200 Boeing 737 MAX jets on order, while Vietnam Airlines HVN.HM signed a provisional deal for 50 in 2023 during a visit to Hanoi by then-U.S. President Joe Biden.

(Reporting by Phuong Nguyen and Francesco Guarascio in Hanoi and Lisa Barrington in Seoul; Editing by Jamie Freed)

((Phuong.Nguyen@thomsonreuters.com; +84-24-3852-9623;))