MANILA -- Government officials have been banned from traveling to Canada, following a delay in the return of a garbage shipment to the North American country, Malacañang said Sunday.

Manila earlier this month recalled its representatives to Ottawa after it missed a May 15 deadline to retrieve toxic waste shipped to the Philippines in 2013 and 2014.

Executive Secretary Salvador Medialdea, in a memo dated May 20, directed "all department secretaries and heads of agencies, government-owned and controlled corporations and government financial institutions to refrain from issuing travel authorities for official trips to Canada," Presidential Spokesperson Salvador Panelo said a statement.

The memo also ordered agency heads to "reduce official interaction with representatives of the Canadian government," he said.

These directives "are consistent with our stance on the diminished diplomatic relations with Canada," added the Palace official.

President Rodrigo Duterte in April said he wanted the trash shipment returned to Canada's shores, even warning that the issue might spark a war.

• Duterte threatens ‘war’ vs Canada over trash shipment

The President has instructed the appropriate office to look for a private firm to ship Canada's trash back to its shores, Panelo said Wednesday.

• PH rejects Canada's move to take back trash by end June

Apart from the garbage row, ties between the Ottawa and Manila also soured after Canadian Prime Minister Justin Trudeau in 2017 raised concerns over Duterte's drug war.

• Duterte says insulted by Trudeau's move to raise human rights

Last year, Duterte cancelled a $233-million military chopper deal with Canada.