Malaysia said it will soon dispatch a letter to Singapore's ex-premier Lee Kuan Yew over remarks he made about Malaysia's ethnic minority Chinese being mistreated.

Deputy Prime Minister Najib Razak, who last week labelled Lee's comments "naughty," told reporters Prime Minister Abdullah Ahmad Badawi would be asking Lee for an explanation.

Asked when the letter would be sent, he replied: "I'm sure shortly, as the PM had made a public undertaking.

"The PM has asked for clarification from Lee Kuan Yew," he added.

According to reports, Lee, now holding the post of minister mentor, told a forum in the city-state earlier this month that Malaysia's minority Chinese community was being systematically marginalised.

He also said it was vital that predominantly ethnic Chinese Singapore stand up to its majority Muslim neighbours Malaysia and Indonesia.

His comments have drawn fire from Malaysian politicians.

Not smooth sailing

Abdullah said at the weekend Lee's comments were unjustified and could inflame Malaysia's minority ethnic community.

Malaysia's government promotes its record of maintaining racial harmony but there are concerns about increasing polarisation and a lack of social unity.

Abdullah, who said he would write to Lee, also said any instability in Malaysia would affect Singapore, which he said had problems managing its own communities.

"We know that they too have problems, it's not 100 percent smooth sailing," he was quoted as saying by the state Bernama news agency.

While Malaysia's 26.6 million people consist of some 60 percent Malay Muslims, the economy is largely controlled by ethnic Chinese who make up 26 percent of the population.

Malaysia and Singapore have strong economic ties but the two nations have squabbled periodically since Singapore was ejected from the new Malaysian federation in 1965 due to race politics.