Prime Minister Tony Abbott says he was simply reminding Indonesia about the "strength and depth" of the friendship of the two countries when he highlighted Australia's 2004 tsunami aid effort during his pleas for mercy for the Bali nine pair on death row.

In his strongest remarks to date in the plea for mercy for Andrew Chan and Myuran Sukumaran, Mr Abbott on Wednesday urged Indonesia to "reciprocate" for the $1 billion in aid Australia contributed in the wake of the 2004 Boxing Day tsunami and pointed out that Australians also lost their lives helping with the recovery effort.

Indonesia reacted hotly, with foreign affairs spokesman Arrmanatha Nasir saying: "Threats are not part of diplomatic language. And from what I know, no one responds well to threats."

But when asked if he was threatening Jakarta with Australia's humanitarian aid, Mr Abbott said he was simply highlighting the long and continuing friendship Australia has with Indonesia.