Singapore's Ministry of Health has upgraded the alert level for swine flu, local media reported on Tuesday.

The ministry said it has changed the alert level from green to yellow, which is in line with the World Health Organization which raised the pandemic alert phase from three to four, according to the local radio 938live.

The ministry said raising the alert level would better brace itself to handle isolated imported cases.

No human infection cases of swine flu have been reported in Singapore.