Malaysian police said on Sunday they had arrested seven militants belonging to ISIL who were plotting violence, one of whom was in contact with an extremist blamed for the deadly Jakarta attack.

Malaysian police said on Sunday they had arrested seven militants belonging to the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group who were plotting violence, one of whom was in contact with an extremist blamed for the deadly Jakarta attack.

Thirty rounds of ammunition was also seized along with books and videos about jihad and an ISIL flag during a series of raids around the country since Friday, national police chief Khalid Abu Bakar said in a statement.

The statement did not mention the confiscation of any weapons or explosives but said the group was planning attacks around Malaysia.

One of those arrested had been in communication with Indonesian extremist Bahrun Naim, the statement said.

Naim is believed to be the founding member of a Southeast Asian offshoot of the ISIL group.

Indonesian police say Naim orchestrated - from ISIL-held territory in Syria - the gun and bomb assault in Jakarta on January 14 that killed eight people including the four attackers.

Two days after the Jakarta attack, Malaysian police said they arrested a man who was planning a suicide bombing in Malaysia in the ISIL's name.

Security forces have been put on high alert in Malaysia in the wake of the Jakarta attack, which has been claimed by the ISIL group.

But concern has risen in the multi-faith nation, with authorities saying scores of Malaysians had gone to join the ISIL in Syria and Iraq.