Online display advertising spend in India, China, Japan, South Korea and Australia will grow from $20.7 billion in 2016 to $38.1 billion in 2021-a 13 per cent growth rate-US-based market research firm Forrester said on Thursday.

India will have the fastest mobile display growth rate but since the country only represented 2.5 per cent of the Asia-Pacific overall display spending in 2016, its impact will be minor, the report added. 

"Mobile display spending will grow from $9.1 billion in 2016 to $28.8 billion in 2021 at a CAGR (compound annual growth rate) of 5.9 per cent. Mobile is the key growth driver for overall APAC display, while desktop/laptop display spending will decline from $11.6 billion in 2016 to $9.4 billion in 2021 at a CAGR of -4.3 per cent," Forrester said.

However, mobile ad blocker usage is widespread in India and China and could become a drag on mobile ad spending even as mobile media consumption expands. 

Australia's mobile share of display is similar to that of the US which is relatively low. Also similar to the US is the fact that Facebook has a much stronger presence in Australia than in other Asia-Pacific countries. 

"Because Facebook is very good at monetising mobile ads, it cannibalises mobile ad dollars that might otherwise go toward mobile display, leading to a relatively lower mobile display share," the report added.