Sports training in the country needs to focus on mental strength to boost national athletes' capability to be more successful at the top level, said Datuk Seri Najib Tun Razak.

The Prime Minister said the national sports development programme had succeeded in raising the fitness bar of the athletes.

"This (mental strength) is for the athletes to have a greater hunger to be world champions not only for the country but for themselves," he said in an audio message uploaded on his official blog NajibRazak.com.

He said the national contingent's achievement of winning four silver and a bronze at the Rio Olympics was Malaysia's best ever in the world's most prestigious sports meet since the country first participated in the Games in 1956.

Najib said the success was an invaluable service by national athletes.

"No matter the performance achieved, our athletes united all of us, irrespective of political leanings or background, all of us were of one heart, one soul in supporting our "wira" and "wirawati" (heroes and heroines) in Rio (de Janeiro), Brazil," he said.

Najib said each Malaysian played an important role in providing moral support to the national Olympians because this spirit is what makes Malaysia strong.

He said this support will help national athletes reach greater heights more so with Malaysia hosting the 2017 SEA Games and the Tokyo Olympics coming up in 2020.

On a personal note, the Prime Minister said the 59th National Day celebration this year would be all the more meaningful following the great success at the Rio Olympics.