* Vietnam relies on imports for over two-thirds of its

jet fuel

* Regulator says Vietnam's refineries cannot

significantly boost jet fuel output

* Vietnam has reached out to China and Thailand, seeking

help

By Phuong Nguyen and Francesco Guarascio

HANOI, March 16 (Reuters) - Vietnamese authorities have

warned the country's aviation industry to prepare for potential

flight reductions from April after China and Thailand halted

exports of jet fuel due to the Iran war, increasing the

likelihood of shortages.

Vietnam imports more than two-thirds of its jet fuel needs,

with 60% coming from China and Thailand, according to documents

from the aviation regulator and importers seen by Reuters.

"There are risks of jet fuel shortages for Vietnamese

airlines from the beginning of April and the following months,"

the Civil Aviation Authority of Vietnam said in a March 9

document sent to the ministry in charge of transport.

It said airlines should review their plans, especially for

domestic routes, and instructed airport operators to prepare

additional parking space for Vietnamese carriers "in case they

have to cut down on operations due to lack of aviation fuel."

Vietnam has also seen reduced supplies from Singapore, the

document showed.

In separate documents viewed by Reuters, major importers

Petrolimex and Skypec said they could only guarantee jet fuel

supplies for March, warning April contracts may not be fulfilled

by suppliers. Skypec urged the regulator to restrict air

transport to essential domestic routes if the conflict drags on.

All documents were issued after China urged its refiners not

to agree to new exports early this month but preceded a hard ban

on refined fuel exports from March 11. Thailand banned exports

of fuel oil on March 6 to all countries except Myanmar and Laos.

The regulator, the ministry and the two importers did not

respond to Reuters requests for comment. Vietnam's top airlines

Vietnam Airlines and VietJet declined to

comment.

DIPLOMATIC EFFORTS MADE

Vietnam was the third-largest buyer of aviation kerosene

from China last year after Australia and Japan, according to

Chinese customs data.

The Southeast Asian country has taken up the issue with both

China, its main supplier, and Thailand.

On Sunday, Foreign Minister Le Hoai Trung asked his Chinese

counterpart Wang Yi for close coordination "to ensure energy

security," in a meeting in Hanoi that had been long planned,

according to the Vietnamese government's news portal.

The topic of energy security was not mentioned in the

Chinese readout of the meeting.

On Friday, Prime Minister Pham Minh Chinh asked Thailand to

help address the shortage during a meeting with the Thai

ambassador in Vietnam, state media reported.

The foreign ministries for Vietnam, China and Thailand did

not immediately respond to requests for comment.

Vietnam's aviation authority noted in its document that "in

the current context it is difficult to find new suppliers."

It added that Vietnam's two refineries are under pressure to

expand production of other oil products, making it hard for them

to increase jet fuel output.

Even if supply stabilises, soaring fuel prices are

disrupting the industry, it also warned, noting many routes

would become unprofitable.

Local airline Sun PhuQuoc Airways plans to "adjust flight

schedules over the next one to three months due to the

volatility of fuel prices," according to a document it sent to

the aviation regulator in March.

The company did not respond to a request for comment.

Petrolimex and Skypec also flagged that the spike in jet

fuel prices has meant they are quickly reaching limits on credit

lines and urged banks to offer more flexible financing until

market conditions normalise, the documents showed.

Front-month jet fuel paper swaps in Singapore on a cost and

freight basis are trading at around $157 a barrel, more than

one-and-a-half times higher than pre-conflict levels, LSEG

pricing data shows.