Autopsies have been conducted on the elephants, which included six cows, but a final report had not yet been released, he said.
Amaratunga added that 293 elephants were murdered in the first nine months of this year, while 93 people were killed by wild elephants straying into villages near wildlife sanctuaries.
Last year, 319 elephants were murdered while 96 people were killed by elephants, official data showed.
Amaratunga said the government will also set up a 500-acre (202 hectares) sanctuary to home 47 tamed elephants seized from owners who did not have licences to own them.
The owners are being prosecuted for stealing the elephants from national wildlife parks over the last decade and keeping them as pets. Capturing wild elephants is illegal.
Many rich Sri Lankans keep elephants as pets to show off their wealth, but there have been numerous complaints of ill treatment and cruelty.
Official records show there are about 200 domesticated elephants in a country where the population in the wild is estimated at between 6,000 to 7,500.