Democratic Labour Party senator John Madigan has slammed Clive Palmer for verbally abusing senate staff last week – and criticising them again on Monday – saying Mr Palmer’s behaviour has set a “very bad precedent".

Mr Palmer reportedly yelled at senate staff on Wednesday evening last week when they ruled that one of his party’s amendments to the Coalition’s carbon tax repeal bill was unconstitutional.

Their ruling made the negotiation over the Coalition’s repeal bill tumultuous, throwing into confusion the government’s attempt to repeal the tax quickly and leaving Environment Minister Greg Hunt and Senate leader Eric Abetz to explain the confusion to media.

But when asked on Monday if he had yelled at clerk of the Senate Rosemary Laing, Mr Palmer said he never raised his voice at her – he only threatened her with an injunction from the High Court to force them to circulate his party’s amendment.