BANDAR SERI BEGAWAN (Reuters) -Vietnam Airlines will issue requests for proposals to aircraft manufacturers next year to purchase 50 narrowbody jets, its CEO said on Wednesday.

The carrier last year signed a provisional deal with Boeing ( BA ) for 50 737 MAX planes that has yet to be finalised.

"In Vietnam we have to go through the bidding process, we have to open to others... The door is still open for everyone," Vietnam Airlines CEO Le Hong Ha told Reuters on the sidelines of an Association of Asia-Pacific Airlines event in Brunei. "Boeing ( BA ) is one option, they have a very good offer for us."

Airbus and Boeing ( BA ) are the main global manufacturers of single-aisle aircraft, with Airbus' A320neo family competing against the 737 MAX, though Chinese planemaker COMAC is trying to make inroads with its C919.

Vietnam Airlines' current narrowbody fleet consists of only Airbus planes, its website showed.

The airline needs 170 new aircraft by 2035, its CEO said.

The requests for proposals leave open a possibility for COMAC to offer the C919. China has increasingly been marketing its planes to Vietnam.

Vietnam's Prime Minister Pham Minh Chinh met a senior COMAC official last week in China who said the Vietnamese market had strong potential, Vietnam's state news agency reported.