Yemeni President Ali Abdullah Saleh will ask King Abdullah of Saudi Arabia to block the flow of funds from Yemeni expatriates to separatists in the south, a Yemeni government source said on Sunday.

Yemen, which is trying to shake off an image of violence to promote its tourism sector, has witnessed frequent clashes between government forces and protesters in the south, where secessionist sentiment is strong.

"Saleh will be discussing the situation in Yemen with King Abdullah, and the activities of some of the Yemeni opposition living in Saudi Arabia," the source said.

The talks will tackle "measures against individuals raising donations to support the protests in the south", he said.

People in the south, home to most of Yemen's oil facilities, have complained that northerners abuse their unity agreement to grab their resources and discriminate against them.

Saleh was due to arrive on Sunday in the kingdom, Yemen's wealthy neighbour which hosts tens of thousands of Yemeni expatriates, mainly labourers seeking higher income.

Saudi Arabia and Yemen, one of the poorest countries outside Africa, are allies of the United States and are partners in the fight against al Qaeda-linked Islamists.

Saudi Arabia, the world's largest oil exporter, has said it fears instability in Yemen could allow it to become a launch pad for a revival of a 2003-2006 campaign by al Qaeda militants to destabilise the rule of the Al Saud family.

Last week, minority Shi'ites asked the Saudi government to end discrimination in the remote Najran province bordering Yemen.

In 2000, Najran was the scene of clashes between the police and hundreds of Ismailis, followers of a Shi'ite sect.

"I think Saudi Arabia is very worried what is happening in Yemen because Saudi Arabia has a 800-km (494-mile) long border with Yemen," said Khaled Dakhil, a Saudi political analyst.

"I think there are so many things they (Saudis) could do; intelligence, political, financial (help)." (Reporting by Mohammed Ghobari in Sanaa and Ulf Laessing in Riyadh; Writing by Jason Benham; Editing by Inal Ersan)