KUALA LUMPUR, May 21, 2009 (AFP) - Malaysia's new premier Najib Razak begins his first official visit to Singapore Thursday, with plans to rise above the long-running quarrels that have undermined relations between the neighbours.

Malaysia wants to promote the massive Iskandar economic corridor in southern Johor state - separated from Singapore by a narrow waterway - which must attract investment from the city-state to succeed.

"It is incumbent upon our two governments to not allow some difficult - or if you like, thorny - bilateral issues to impede and hamper whatever progress we can achieve," Najib said in an interview with the Singapore Straits Times.

"I hope that the relationship will continue to improve in the years to come," said Najib who was sworn in as prime minister in April.

He told the daily that as well as the Iskandar project, which will be high on the agenda of his meeting with Singapore's leader Lee Hsien Loong, he would push for more cooperation on trade, tourism, security and defence.

Najib will begin the two-day visit by crossing overland into Singapore, via one of the two bridges that link the two countries.

Malaysia's ambitions to build a new bridge to replace an ageing and overcrowded causeway triggered intense friction between the two neighbours, and the plans were controversially dropped in 2006.

It was just one of the disputes that have periodically rocked relations since Singapore was ejected from the Malaysian federation in August 1965 - an episode that still rankles on both sides of the causeway.

The rows have included the price of water that Malaysia supplies to resource-scarce Singapore, Singapore's military access to Malaysian airspace, and the future of Malaysian-owned railway land inside the city-state.

However, since the departure of combative former premier Mahathir Mohamad in 2003 the relationship has warmed, said Ooi Kee Beng from the Institute of Southeast Asian Studies in Singapore.

"And now with a new prime minister I think one of his major immediate goals is to show Malaysia's neighbours that he's open to cooperation and to solve problems," he said.

"Given the global crisis, the Iskandar project has to succeed and they do need Singapore for that." The government hopes to attract 105 billion dollars in investment over 20 years for the Iskandar Development Region, which would be 2.5 times the size of Singapore.

However, ambitions of turning sleepy Johor into a bustling commercial centre have been hampered by a reputation for crime and disorder, which has deterred Singaporeans from doing business or living there.

Ooi said that all the lingering issues between the neighbours, including a possible revival of the bridge project, could be on the table during Najib's visit.

Najib told the Straits Times he would like to get some major projects off the ground, and to "facilitate the movement of people between our two sides." Ooi said the neighbours may discuss extending Singapore's mass-transit rail into Malaysia, and electronic passports that would enable citizens to cross the border without going through two sets of immigration controls.

"I'm sure there is room still for negotiations. I wouldn't rule out a future bridge," he said.