There was no immediate comment from the Guinness organisation on whether the event had met the requirements to claim the record.
Many of the twins - including children, pensioners and police officers - had travelled for hours to attend the event, which had Sri Lanka's prime minister, Mahinda Rajapaksa, as guest of honour.
Hamna, Shahna (12), Umaira, Umaima (12) and Radha, Rana (12) pose for photographs during an event to attempt to break the world record for the biggest gathering of twins in Colombo, Sri Lanka January 20, 2020. REUTERS/Dinuka Liyanawatte
"It's fascinating," said Raheen Usman, a 19-year-old from Colombo, there with her twin Farheen.
"I have made a lot of new friends - all of my friends are twins now."
The record-breaking attempt was followed by a concert performed exclusively by twins, including an 80-member orchestra.
The campaign group Sri Lanka Twins said it had organised the event to raise the profile of underprivileged twins, triplets and quadruplets. Poorer families often struggled to cope with multiple births, it added.
(Reporting by Dinuka Liyanawatte and B. Channa Kumara in Colombo, writing by Alasdair Pal; Editing by Andrew Heavens)