Bill Shorten says Tony Abbott is at the heart of the chaos and division in the Turnbull government and he’s not going away.

Reports suggest the former prime minister will be electioneering in marginal seats on his own national tour after being snubbed of a proper campaign role in what is likely to be a 2 July double-dissolution election.

“The only way you don’t get Tony Abbott is by voting Labor because Mr Turnbull can’t stop Tony Abbott,” the opposition leader told reporters after serving lunch with his wife, Chloe, at Sacred Heart Mission in St Kilda on Sunday.

Turnbull kept a relatively low profile on Sunday, other than attending Easter mass in his Sydney electorate of Wentworth with his wife, Lucy.

A junior minister, Angus Taylor, said he had no problem with Abbott making a contribution to the policy debate, as he had done for many years.

“He will carve out his own role as a backbencher which all backbenchers do in an election campaign,” Taylor told Sky News.

But the former Liberal leader John Hewson said he believed the prime minister should give him a job.

“He won’t go away, so I think you give him a role. Define the role very carefully and encourage him to be judged by his performance,” Hewson told Sky News.

Hewson also expressed surprise at the plaudits that Turnbull was getting for his strategy to force a 2 July poll. Rather than being a stroke of genius, he said he believed it was “quite high risk”.

Turnbull is bringing parliament back on 18 April to have another crack at getting legislation to restore the construction watchdog through the Senate, and if this fails for a second time, as seems likely, it will be a trigger for a 2 July poll.

But Hewson said if the Senate unexpectedly supported the reintroduction of the Australian Building and Construction Commission, it would delay an election to September or October.

“In the interim he has got to deal with issues like [Arthur] Sinodinos, Abbott, backbench issues and a budget that has been neutered as a pre-election budget rather than a reform budget,” Hewson told Sky News on Sunday.

The government needs six of the eight crossbench senators to back the Australian Building and Construction Commission legislation, with Labor and the Greens opposing the bill. Four have said they will support it, while the other four won’t say.

The former Labor minister Craig Emerson said it was strange the prime minister had left the timing of the next election in the hands of four senators “who hate his guts”.

“That’s a master stroke, apparently,” Emerson said.