Glenn Maxwell admitted he "wasn't expecting" to hit a record 40-ball Cricket World Cup century on Wednesday.

Maxwell, nicknamed 'The Big Show' for his flamboyant hitting, clubbed eight fours and eight sixes in his run blitz as Australia piled up 399-8 against the Netherlands in New Delhi.

The stunning assault bettered the record of South Africa's Aiden Markram who blasted a century off 49 balls against Sri Lanka at the same venue 18 days ago.

"It feels pretty good. I have been pretty cooked today so I wasn't expecting much but it probably cleared my head a little bit to be able to go out there and play," said Maxwell.

It was also the fourth fastest century in all ODIs.

South Africa's AB de Villiers leads the way with his 31-ball century against the West Indies in Johannesburg in 2015.

New Zealander Corey Anderson reached three figures off 36 balls against the West Indies at Queenstown in 2014 while Shahid Afridi of Pakistan made a century from 37 deliveries facing Sri Lanka in Nairobi back in 1996.

The 35-year-old Maxwell, playing in his 133rd ODI, was eventually out for 104, just short of his career best 108 made against England in Manchester in 2020.

It was also comfortably his best score of this World Cup -- his highest before Wednesday was 31 not out against Sri Lanka in Lucknow.

"I was just trying to get a read on the bowlers because I felt like I had enough time to change and adapt. Generally I am just trying to get any reverse sweeps over the infield.

"I thought the Netherlands were outstanding. It felt like they saved some certain boundaries in the first 25-30 overs.

He added: "It is a rock hard outfield. The ball can travel around here so if you get early wickets and get into the middle order, you can put run-rate pressure on them."