He brushed off discussion in the British press on whether On Chesil Beach was a novel or a novella and questions over whether it should have been entered for the Man Booker prize. "That's their problem, not mine," he said.Quite.
The same article in the Australian also points out that Mohsin Hamid's The Reluctant Fundamentalist (which I'm reading at the moment) is only 45,000 words long. Thought I was zipping through it rather fast.
As if to answer the question, just came across this passage in Mohsin Hamid's book:
"It's done," she said solemnly. I waited for her to say more, and when she did not, I asked, "'It' being?" "My manuscript," she said "I'm sending it to an agent tomorrow." I took it respectfully in both hands, resting it flat across my upturned palms. "Congratulations," I said, and then noticing it was rather light, added "Is that all of it?" She nodded. "It's more a novella than a novel," she said. "It leaves space for your thoughts to echo."