The Singapore government has postponed a bilateral discussion with Malaysia after it accused Johor Menteri Besar Osman Sapian of sailing into waters claimed by both countries.

"The intrusion by Johor Menteri Besar Osman Sapian into Singapore territorial waters off Tuas on Jan 9 made the 14th Joint Ministerial Committee for Iskandar Malaysia (JMCIM) meeting untenable.

"Singapore, therefore, proposed to postpone the JMCIM meeting and Malaysia agreed," the Singapore Foreign Ministry said in a statement today.

Osman, who visited the area onboard the MV Pedoman, denied intruding into Singapore waters.

Unlike other parts of the Johor Straits, the maritime border off Tuas was never clearly defined.

Read more: The M'sia-S'pore maritime dispute illustrated

Since 2002, Singapore had been reclaiming the waters off Tuas, extending its land southwards where there is no defined border.

Until October 2018, both Malaysia and Singapore's port boundaries had avoided the area.

However, in October, Malaysia extended the Johor Bahru Port boundary into the area, claiming that illicit activities were taking place and that it was unpatrolled by Singapore.

Singapore denied this, and extended its own port boundary into the same area a month later, creating an overlap.