The BN federal government can best honour deceased PAS spiritual leader Nik Aziz Nik Mat is to give Kelantan the oil royalty due to it, PAS said.

PAS information chief Mahfuz Omar says this after Umno Youth chief Khairy Jamaluddin urged BN to stay out of the Chempaka polls to honour the veteran politician who died at 84 last Thursday.

Oil royalty was one of Nik Aziz's greatest struggle who was Kelantan menteri besar for more than two decades, Mahfuz said.

The government of Kelantan had even filed a lawsuit against Petronas for allegedly breaching the Petroluem Development Act 1977, he said.

"Wouldn't it be nice if Prime Minister Najib Abdul Razak fulfilled BN's duties to the people of Kelantan and returning the oil royalty," he said in a statement.

Mahfuz also condemned what he said was an insincere show of respect by BN leaders towards Nik Aziz after his death.

Nik Aziz's funeral at Kampung Pulau Melaka, Kota Baru was attended by thousands and broadcast live on television.

Prime Minister Najib Abdul Razak were among the sea of supporters paying their last respects.

Critics, however, questioned why Nik Aziz was given such post-alive.

BN is still undecided over whether to contest the Chempaka seat which Nik Aziz held since he first joined politics in 1967.

The federal government says Kelantan has no right to oil royalty because exploration is more than 150 kilometres away from the Kelantan shore, but the state says the Act does not stipulate this.