Shorten speaks "severely" to Dastyari

Opposition Leader Bill Shorten has stepped up his criticism of embattled Labor frontbencher Sam Dastyari saying he's spoken severely to the "junior senator".

Senator Dastyari, under seige over the payment of a personal debt by a Chinese company linked to Beijing, had made an imprudent decision but could still make a serious contribution to the nation.

"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.