Embattled Labor Senator Sam Dastyari has apologised for accepting the payment of a personal debt by a company linked to Beijing, saying that the donor asked for nothing in return for the money.

Mr Dastyari has faced a firestorm since it emerged a company called Top Education paid a $1,670.82 travel bill his office incurred last year.

Top Education Institute’s principal is Minshen Shu, an Australian-Chinese businessmen with links to China who has frequently donated to both sides of Australian politics.

Mr Dastyari rejected assertions he was involved in a “cash for comment” arrangement with Chinese donors.

“I completely reject an assertion or implication that .. any of my comments or decisions have been influenced by anything other than the national interest,” he told reporters in Sydney on Tuesday.

Mr Dastyari is under increased pressure over the payment after he made public sympathetic public comments about China’s stance on the South China Sea – contrary to Labor’s position on the dispute.

He said he had not offered his resignation to Labor leader Bill Shorten.

“And I haven’t been asked,” he confirmed.

Labor’s consumer affairs spokesman and manager of opposition business in the Senate said he regretted his actions.

Mr Shorten has not asked for Mr Dastyari’s resignation. Photo: AAP

“I acted first and thought later. The lesson for me out of this is to stop, think and actually reflect first before acting.”

Earlier in the day opposition Leader Bill Shorten stepped up his criticism of Mr Dastyari saying he’s spoken severely to the “junior senator”.

“I’ve spoken to him severely and I’ve made it crystal clear that this behaviour is not the behaviour I expect in the future from him … I am prepared however to give him a second chance,” Mr Shorten told reporters in Melbourne on Tuesday.

Prime Minister Malcolm Turnbull said Senator Dastyari took cash for himself and then expressed a view at odds with his party’s foreign policy.

“What Mr Shorten is seeking to do is distract attention from the very real failure of his leadership in not removing Sam Dastyari from the frontbench,” he told reporters in Hangzhou on Tuesday.

However, the prime minister would not rule out backing donation reforms saying the issue would be considered by a parliamentary committee on electoral matters in the usual way.

“We will look at it with a very open mind … It is complex area and it’s worth looking at clearly and in a considered manner.”

-with AAP