Thousands of people are attending a rally in Malaysia's capital, Kuala Lumpur, in support of the government.
The organisers, members of the ruling United Malays National Organisation (Umno), say they want to "uphold Malay dignity", leading to fears the march could stoke racial tensions.
It follows opposition rallies two weeks ago demanding that PM Najib Razak step down over a financial scandal.
Unmo said those rallies were attended by anti-government ethnic Chinese.
Race-relations are fraught in Malaysia, where ethnicity dominates politics.
Malays make up about two-thirds of Malaysia's population and play prominent roles in government and the civil service. Ethnic Chinese represent about a quarter of the population but own considerably more than that share of the wealth.
Organisers of Wednesday's march said it was call for respect for ethnic Malays.
"We will not provoke anyone or spark a racial clash. We will not riot," said Jamal Yunos, a key organiser and a senior Umno official.
People attending Wednesday's protests have been asked to wear red - the colour of the ruling party - to counter the distinctive yellow T-shirts worn by protesters at the late August rallies.
Security has been increased around Chinese areas of the capital, while many Chinese-run business have remained closed.
Ever since deadly sectarian riots in 1969 Malaysian governments have usually been keen to clamp down on overt racial provocations.
Deputy Prime Minister Ahmad Zahid Hamidi said any banners with "sensitive" wording would be confiscated.
Mr Najib, the president of Unmo, has not officially endorsed the rally but has allowed it to go ahead.
Last month, tens of thousands of people marched through Kuala Lumpur and other cities demanding Mr Najib resign amid allegations he personally profited from a state investment scheme.
He had denied the allegations, and Malaysia's anti-corruption agency has said the money came from foreign donors.
The Umno-controlled governing coalition has been in power since Malaysian independence in 1957.
But it has lost support in recent years as Chinese voters have moved to the multi-racial opposition, prompting an increasing use of anti-Chinese rhetoric by Malay hardliners.
The march is going ahead despite a thick haze enveloping the city, caused by illegal forest fire clearances in nearby Indonesia. Singapore and Indonesia itself are also badly affected.