Mr Howard said several leaders raised the issue at a gala dinner on Tuesday night ahead of Wednesday's East Asia summit.
"It was mentioned informally, yes," he told reporters.
"A few people just asked about it and we chatted about it over a drink before the dinner."
The meeting's host, Malaysian Prime Minister Abdullah Badawi, reportedly discussed the riots behind closed doors on Tuesday with other leaders.
Mr Badawi's predecessor and long-term critic of Australia, Mahathir Mohamed, separately said the riots indicate Australia is a racist country at heart, however Mr Howard dismissed this.
Large police presence
New South Wales Premier Morris Iemma said hundreds of police will be present in flashpoint suburbs.
Early on Wednesday morning, a Uniting Church hall in the suburb of Auburn, which is next door to an Islamic centre, was set ablaze.
Police are treating the blaze as suspicious.
It followed an incident in nearby St Joseph the Worker Primary School, in which shots were fired into cars during a Christmas carols service.
Mr Iemma warned that a 500-strong anti-riot squad will be in force over summer to deal with race-fuelled violence.
In other violence on Tuesday night, a motorist was bashed with a baseball bat and five people arrested.
About 450 officers were on patrol overnight in flashpoint suburbs in the south and west in the wake of Sunday's race riot at Cronulla.
NSW Assistant Police Commissioner Mark Goodwin said there were no "smash and bash" raids and no confrontations with police.
Racist anger spreads
Police say text messages which fuelled Sydney’s race riots have now turned up in two other states.
Mobile phone text messages calling for people to start cracking skulls have surfaced on the Gold Coast.
Deputy Commissioner Andrew Scipione has said similar messages have also been reported in Victoria.
Riot meetings
Australian Muslims and Christians have met in Sydney to try to resolve the violence which has plagued Sydney's southern suburbs.
A number of community meetings have been held, with police and representatives from Cronulla and nearby areas also taking part in the talks.