Australian bank Macquarie Group’s aircraft leasing subsidiary is in exclusive talks to buy a portfolio of new planes from Dublin-based leasing firm AWAS for more than $4bn, according to people familiar with the matter.

Macquarie Air Finance is negotiating a deal for just under 100 newly built and on-order aircraft being sold by AWAS, the people said. 

Macquarie is working to finalise an agreement before the end of January, they said, asking not to be named because the matter was confidential.

Asia has become the world's fastest-growing aviation market as airlines seek to tap into the rising spending power of the region's travellers, attracting the attention of aircraft lessors and manufacturers.

Macquarie declined to comment.

Reuters reported in September that other suitors for the AWAS aircraft portfolio were Japanese firms Orix Corp and SMBC Aviation Capital, owned by Sumitomo Mitsui Financial Group. 

Hong Kong Aviation Capital, which is owned by China's HNA Group, and Bohai Leasing Co. Ltd, were also in the hunt.

AWAS, one of the world's biggest aircraft lessors, is owned by British private equity firm Terra Firma Capital Partners and has more than 300 planes on lease to over 110 airlines. AWAS and Terra Firma both declined to comment.